Does Water In Brake Fluid Cause Rust Or Damage?

Note: I will update this page as the experiment goes forward.

Many times we hear how important it is to change the brake fluid often because it is hygroscopic (absorbs water). Then the marketing materials continue about rust forming, exploding brake lines, destroyed rubbers, boiling water and fluid needing to be changed regularly.

The brake fluid is cheap, but it is one of those things which has environmental impact and also monetary cost increase if you keep changing many fluids unnecessarily. Plus, there are literally billions of vehicles use it. Imagine the yearly liquid amount which should be recycled.

Businesses constantly scare people so they keep up with the regular payments. Considering there are over billion vehicles in use. Can you imagine the regular revenue stream from regular purchases of a product like brake fluid. There is no business like fluid business.

Should we be scared of boiling water, rust and corrosion? But we can't see the rust inside the pipes. Is there rust really? or is it a convenient way for companies to scare us? Will the brake pipes burst if we do not change the brake fluid often enough?

Reasoning:

As we all know forming rust requires oxygen. Therefore it should not happen inside brake pipes (because we do not have air in the brake pipes!). Somebody may say, water carries dissolved oxygen what about that? The absorbed water by the brake fluid will not contain oxygen. Because oxygen molecules will not be absorbed by brake fluid.

What about disintegrating rubbers? Brake fluid attacks many things by itself. But having water inside will not cause it to destroy rubbers. Totally made up.

So there remains boiling water. Yes, the brake pad temperatures can reach 200C or higher. But the heat transferred to caliper and the brake fluid is less and locally isolated (the only hot part is around the caliper where piston touches the pad) The absorbed water decreases the boiling temperature of the brake fluid. For dot 5.1 the wet (3.7% water) boiling temperature goes down from 270C to 190C. So it may be possible that a very small amount of brake fluid may boil. But all things considered, it won't cause catastrophic brake failure all of a sudden.

Experiment:

It is simple, I have created a 10% water mixture with brake fluid and dropped copper/steel materials into it.

Preperation:

Used 2 washers, 2 galvanized steel nuts and 2 copper nuts. First I put them into vinegar to artificially rust away the galvanization layer. Since it would just make the rust appear slower.

In the picture above, untouched washer and nut can be seen on the left lower side. Also a set of nuts and washer are in the glass. The other 3 goes to the other glass.

I fill one of the glass with brake fluid which had about 10% water and the other glass is filled with water. I used tap water and it may effect the results compared to brake fluid absorbing water from air directly. However I didn't want to wait for that to happen and I could control the amount of water inside brake fluid better if I put it there myself.

Below is 2cl brake fluid ready to be mixed with  2.5ml water.

Tested the solution using brake fluid tester

Now that the brake fluid tester is proven to be functioning. I have mixed the brake fluid/water in the glass also.

You can see the glass with water on the left also.

Then had to cover the tops with cling wrap to avoid contamination. However I made a 3rd glass where was pure brake fluid with holes on its cling wrap. That is there for following the absorption of water from air (a side experiment)

I may open the cling wrap once in a while and air the fluids, but it should be even better to keep the fluids covered. Because brake fluid system itself is a closed system and keeping the cling wrap will help to emulate it better.

Day 1 (28-Dec-2018):

After few hours of waiting the items in the water glass were covered with bubbles. Then they developed some rust. There was also water condensation on the cling wrap.

I realized that I forgot to wipe the rust from vinegar inside the washer which is in brake fluid. But that is not important. Otherwise there is nothing happening to the items in the brake fluid right now. Also there is no condentation on the cling wrap.

Day 2 (29-Dec-2018):

Actually, it has been less than 24 hours but there is significant progress in the water cup compared to the brake fluid cup. There is no change on materials inside the brake fluid.

Day 8 (05-Jan-2019):

Not much difference visually. The copper nut seem to have lost its copper plating in water. The water seem to have much more particles floating at the bottom. No difference to parts in brake fluid.

Day 17 (14-Jan-2019):

No difference to parts in brake fluid. It is nearly impossible to see the parts inside the water. I will  replace the water with clean water before continuing. Otherwise it will be impossible to see anything there soon.

Day 122 ( 29-Apr-2019):

Still, no difference for parts in brake fluid. The parts inside the water are totally gone under rust pieces.

Conclusion:

At this point I am stopping the experiment as it has been nearly half a year and there is definitely degradation with parts in water but nothing visible with parts in oil.

After rinsing the parts which were under water.  I can see some degradation

However they still seem perfectly fine otherwise!

Also checked the brake fluid glass with air holes on top. It have collected about 3% water in this time. So yes, brake fluid absorbs water.

But overall, it is clear that we do NOT have to worry about water in brake fluid causing rust in the brake system. It seems to be impossible.

BM Catalysts BM91248H vs VW 1J0 254 400 HX

This part from BM Catalysts is usable. However there are differences in production quality and I would recommend using a slightly better aftermarket product from another company or genuine VW item. ( 1J0 254 400 HX , 1J0254400HX , 1J0254400 )

First difference is that BM Catalysts part is 2.1kg and genuine VW part weights 2.8kg

Another difference is that the catalytic converter itself is much further away in BM Catalysts product compared to genuine VW product.

This cause the bulged part to sit slightly more back compared to original catalytic converter. Probably this is due to production margins and bolt lengths the BM Catalysts is using. This looks quite ok when installed. But there is more space on the front part of the car. (probably space left specificly for catalyst).

Now the real problem with this product is that the catalytic converter is thinner but longer. BM Catalysts part has radius about 9cm length of 16cm meanwhile the genuine VW part has radius of 13cm and a shorter length. This means that the BM Catalysts product will restrict gas flow more than the genuine VW part.

I guess BM Catalysts save money using one size fits all approach. So same catalytic converter piece is welded to different products.

I would recommend getting the genuine VW item or a catalytic converter which resembles the genuine item more closely.

BM Catalysts BM70455 vs VW 1J0 254 300 P

I made the mistake of buying this pipe assuming it would have been built to same specs. However it seams the company called BM Catalysts is making very very poor quality products and you should not consider their products.

Look at the difference between the BM Catalysts and VW front exhaust pipe. ( 1J0 254 300 P , 1J0254300 , 1J0254300 P )

First picture is the genuine VW pipe. It has a more defined curve and it fits perfectly to the car.

Below is the BM Catalysts part. 

Unfortunately BM Catalysts has very short flex piece and does not provide enough flexibility. Also the part is also missing the heat shield just after the flex piece which protects the steering axle boot from heat. Because of this, it should never be used!

When the BM Catalysts part was installed on the vehicle, it caused vibrations between 1800RPM - 1900RPM and since the VW part is installed, there is no more problems.

Below you can see how the parts fit just before catalytic converter. The left part is the BM Catalysts part which fits poorly and the pipe is in wrong position. This cause extreme pressure on the rubber bushes and stop them from working properly.

As you can see, the BM catalysts part is also built in a lazy fashion by just welding a metal pipe under the exhaust pipe. If you look at the genuine VW part, you can see that it has been built more intricately for reducing the heat transfer to the bushes.

The part on the right is the genuine VW part which fits perfectly into place. As you can see, the difference is significant and this give a large difference in how the car feels when driving.

The BM Catalysts part weights roughly 2.4 KG and the genuine VW part weights 3.7 KG. A whopping 50% more! When handling the parts, it is easy to see that genuine VW part has thicker intake manifold connection and the pipe itself feels more robust and built to last.

Below are few more comparison pictures. Unfortunately BM Catalysts exhaust front pipe was not up to the task.

VW Golf Variant MK4 Tailgate Lock Switch Replacement

I have actually done this few years back but now adding it here.

Below is the original switch from the door lock. Unfortunately it was impossible to find the same part.

Below is the replacement switch I found for this project

The new switch was different model number than the old one. The new one has number 6x0 947 569 and old one is 070.767.22.2

I found out the only difference is a tiny extra plastic part on the side of the switch.

The tab is clearly visible in this photo, between the round pillars:

I simply cut the tab out using a sharp knife. Here is the image after cutting the tab. You have to cut it, otherwise it wont fit in place.

This is the lock after removing the switch. After breaking the plastic tabs of the switch, I just used pliers to pull the metal upwards to be able to slide the switch out. Yes you need to bend it!

New switch in place before bending it back to position:

After putting the switch in, I first bent the metal back. This time I put the pliers from the hole where the connector normally goes in. Then bent it inwards carefully. After it looked straight, I pushed the switch in and tested if it contacts properly with the lock mechanism. When everything looked fine. I heated up the soldering iron and slowly melted the tabs to make the switch stick in place. I used some contact glue between just to be sure that it will stay put in place. Here is the finished product (I painted scratches from pliers ith black paint). It doesn\t look as tidy as the original tabs but works fine.

I guess it would have been better to use a heat controlled soldering iron at about 200C to slowly melt the tabs to location, but I did not have access to one at that time.

Golf MK4 Pollen Filter Cover Design Fault - 1J1 819 537 C B41

This part was all broken in my vehicle due to years of bending when inserting and removing. I thought maybe it was inserted/removed wrong way and that was the reason. However after trying how to insert it literally 20+ different ways I have given up.

It appears VW made a mistake in the design of this item. It is simply impossible to fit into the car without bending some plastic parts which become fragile over the years.

Problem:

In the pictures below, you can see that the bottom of the filter is touching to the frame and the extension on the left won't go under the plastic part which guides the wire.

As you can see below, the part of the filter does not go under the plastic piece on the body. You need to bend the filter cover considerably to be able to fit it in.

This a doublefold problem. First the plastic gets broken due to bending and the body paint is scratched where the lower part touches because you need to slide the pollen filter with force.

How To Fix:

There are 2 ways to solve this, you can cut the plastic piece which gets stuck there or you can lower it by cutting the parts slightly to lower the filter cover. I opted to lower the plastic by cutting from under.

Below is a picture from the side of the pollen filter. I draw an outline of the part which is removed. (may not be exact)

Below is the cut from the front. It almost looks like VW tried to make the same cut but on the wrong place and it became useless. You can see this just right of where I removed the bottom of the plastic. There is a ready groove which is almost the same as the one I needed.

I started removing parts slowly from the side of the filter cover first. Then I removed from the front of it a little bit and went on. After taking of a piece, I put the filter back in position and checked which part is the most tight part and took a piece from there.

I used a normal household scissors for this purpose. Therefore it became quite jagged. So, when I was ready, I took the die/rotary grinder and sanded it smooth. Then went once more by hand to make it really smooth.

After making these changes, the filter cover is now able to enter to housing perfectly without any problems. It should now be able to last forever since no need to bend it ever anymore.

Installation:

After the fix, installation is a breeze...

As you can see, the flap goes readily under the plastic part without any bending.

and you also do not have to bend the filter upwards to get it past the body.

VW MK4 Pollen Filter - 1J0 819 644A

I decided to keep a log of the filters I try and their weights to determine which one is perhaps best value.

WIX Filters - WP 6895 Version With Active Carbon

I had 2 of these. They weighted 122g and 126g. Built in Poland. It looks like active carbon was sandwiched between layers.With a cost of ~9euro, they are pretty cheap.

It fits tightly to my VW Golf MK4 filter box. My only complaint is that the filter has uneven thickness. At some points, you can see the light going through like transparent. This tells me that larger particles can fly through these parts. If you are buying this filter, you should check it by looking through it to see that it has no manufacturing faults.

The box has a list of OEM part numbers which it is compatible with.:

MANN: CUK 2862, FP 2862
KNECHT: LAK63
PURFLUX: AHC178
FRAM: CFA8869
FILTRON: K 1047A

I made a small test with the old filter. I washed it under sink and it seem to keep its shape and do not get destroyed. Perhaps we can call it washable :)

Below are some photos of the item:

 

Chinese Noname Filter 1 (2018)

For a cost of ~6euro it is possible to obtain a filter from AliExpress. I am guessing that they can be made in different factories. So your experience may vary. The filter I received weighted 132g and it had much better construction than the WIX filter. When I looked through it, there was no light going through and it had a uniform thickness.

While it is impossible to tell the effectiveness of the carbon filter part. As it was so tightly woven that the light did not go through, the filter itself probably functions at least better than the WIX filter.

The filter construction seem to have a thick black piece in the middle and thin white microfilter on both sides.

Chinese "Noname" Filter 2 (2019) - OEMMASSIVE

For a cost of ~8euro (well it was cheapest I could find in 2019) it is possible to obtain a filter from AliExpress which is brand OEMASSIVE. It is similar to previous chinese filter in constructions. The difference is that it weights a whopping 257g. More active carbon? Yes please! The manufacturer says "double layer active carbon". It seem to be true!

I am not putting many pictures as it came in a white box and the construction is similar to the previous chinese filter. The difference was that it had a thick microfilter in middle and on both sides of it was harder fiber filters with active carbon attached. This one seems to be much better than the first chinese filter. Unfortunately the box was smashed during delivery. They should have used a better box! I really hope it will stay in form once installed.

However there was some text on side of this filter and here it is.

I do not understand why this filter is difficult to find on AliExpress. Actually it does not appear if I search for "1J0819644A". Only appears when I search for "OEMassive 1J0819644A". More importantly, the sellers does not seem to advertise the weight of it. This filter clearly is very good for the price.

VW Golf MK4 Wiper Base/Mechanism Replacement

I had one of the wiper shafts shear off when tightening a wiper arm. (I used torque wrench to tighten to correct torque value but still..)

I had to go to a local parts shop to get a replacement 3rd party part quickly. Otherwise, it would be impossible to drive the vehicle if it rained. Since it was the drivers side arm's shaft.

In the end, I had to do the same procedure again to install original VW part because the 3rd party part was not a good fit after all. More about that later.

You may want to do this in a warm environment. At least 15+C temperature to not break the plastic parts.

Required Parts

Dow Corning / Molykote 111 Silicone compound for lubricating rubber/plastic parts.

WARNING: These are parts for LHD vehicles and some part numbers are different for RHD vehicles

1x 1J1 955 603 B - Wiper base for LHD vehicles
1x 701955754 - 14X9,5 grommet (attaches to wiper base)
1x 701955756 - Bush (attaches to wiper base)
1x 535 955 121 A - Crank arm (attaches to wiper motor)
2x 1J0 955 325 A - Operating linkage for LHD vehicles (attaches to wiper base and motor crank).
3x N 0143441 - M6X18 hex bolt with shoulder, self-locking (attaches wiper base to body)

If you want to change wiper motor bolts also:

3x N 90305302 - M6X10 hex collared bolt (attaches wiper base to motor). Apparently this item was superseded by N 90305304 but I had some problems with it. More about that later.

Required Tools

Wiper/bearing puller
10mm wrench
13mm wrench
Torx/Philips screwdriver (for pollen filter screws)
Patience

If you are replacing with original VW part, you need to buy wiper base and linkages separately. I recommend getting a wiper crank arm also.

In addition, probably a vacuum cleaner to clean up the space where the wiper mechanism sits. Mine was filled with leaves and soil! Now I know from where all the mud and leaves in my wheel arc was coming from! Yes a perfect compost!  Note to self: Install a net to the water deflector air holes to reduce leaf intake!

1- Remove Wiper Arms

First you need to remove wiper arms. I used a knife to pop up the protective plastic covers on top of the nuts. The nuts are 13mm.

Apparently VW suggests yanking the arms off by moving them left/right/up/down while pulling. You should not remove them this way!

I have loosened the nuts but did not remove them, then set a wiper arm puller in place to pull wipers out. It was not easy even with the wiper arm puller. The area is small so you will need a small enough arm puller. I used 2 different parts for this task.

The one on the left fits fine to remove wiper arms. However I used the one on the right to manipulate wiper base linkages. Some sites say you can use screwdriver etc. but it is a cumbersome process with screwdriver and you may damage connecting pieces with screwdriver.

2- Remove Pollen Filter Cover (1J1 819 537 C for LHD)

Remove the 4 screws which hold the pollen filter cover and remove the cover. This is very useful when removing the trim part which the pollen filter cover was connected to.

3- Remove The Water Deflector (1J1 819 415 B for LHD)

Unfortunately I did not take picture of this. However it is easy. I used a plastic trim removal tool to remove it. You will start removing it from the pollen filter side. I have put the trim removal tool between the deflector and windshield and also pushed it up using my hand from the hole of the pollen filter.

If you are applying pressures at the right place, you will feel that it pops out quite easily. So, try a few different locations. I found out the best place was near the corner of the windshield. Do not force it, you may break it if you force removal. Just take your time!

After removing it, clean both the windshield groove and also the water deflector extension which enters to the groove. Otherwise it won't fit well when you install it back. I used paper towels and just slided them several times to push all the dirt out. As you can see in the picture below.

4- Remove Wiper Base Mechanism

Once the water deflector is away, it is easy to see the wiper mechanism. I took the picture below after installing the new wiper, that is why it is so shiny.

The red arrows point to the 10mm bolts holding the mechanism and the green arrow points to the wiper motor connector.

You will first need to remove the 10mm bolts. Then wiggle the passenger side arm out and then use a flat head screwdriver to carefully remove the wiper motor electric connector before completely removing the base. It is tight, so you need to carefully wiggle it around. Make sure to not make big scratches on your paintwork.

5- Clean The Surrounding Area

I realized the surroundings were filled with soil (surely converted from leaves!) and leaves. You can see below the broken shaft also. This photo was taken when I removed the water deflector first time.

After cleaning what I could by hand, I had to resort to using a vacuum cleaner. The soil was wet so I would not recommend a normal household vacuum unless you change the bag right away after vacuuming.

Vacuuming clean the area pretty good. But I went one step further and washed the area and pushed remaining mud to the draining holes on the sides. While on it, I also removed the mud flaps and empty the collected mud from the wheel arc. Make no mistake, it gets filled with mud and cause rust if not cleaned regularly!

6a- Install Replacement Wiper Base/Mechanism

OK, you think the installation is reverse of removal so why do we need this section? You are correct that installation is pretty much reverse of removal. However I had some experience with a 3rd party part and I would like to relay it as a warning.

Because I was in hurry to fit something there before getting caught on rain. I went to local parts shop and bought a replacement.

Yes, the part is a topran 110 694 which says clearly that it replaces 1J1 955 603B (yes this is exact same part number that we needed). The good thing was that this part came with all the rubber bushings etc. But I think topran made a mistake because this item seem to replace 1U1 955 023 E which has drivers side linkage with part number 1U1 955 215 B and ength 66.5mm. But this is incorrect for Golf MK4. It seems to be for some Skoda models... hmm?

Aftermarket Part Problems

 

a) First of all, I could not properly adjust the driver's side arm to go until the correct position. It kept stopping ~6cm before the original went. I could not lift the resting position 6cm up because then the wiper was too high when resting. First I thought that I made a mistake but it seemed unlikely because wipers were resting exactly where they used to be originally.

I have then compared the linkage arms with the original part to see why this was happening. The arms on the base frame are different length for driver's side and passenger side. you can see this when you operate the wipers. The driver's side goes about 90degrees and passenger side goes ~110 (because it ends in front of the driver as you can see when it is working)

When I checked the original VW wiper part. I realized VW was smart enough to write the linkage lengths.

The passenger side 1J1 955 216 A and 62.3mm. Driver's side 1J1 955 215 A and 64.8mm. Wiper arm travels less when linkage is longer. So if you ever open your wiper frame and oil it, you need to make sure to put them to correct sides.

Now, the 3rd party part got the correct passenger side measurement but the driver's side showed 66.5mm.

So, if you think that driver's side does about 90degree turn with 64.8mm and 110degree turn with 62.3mm It means you get 20degree diffeence using 2.5mm meaning each mm is about 8degree for our purposes. So going from 64.8 to 66.5 is 1.7mm difference. It should reduce range about 13.6 degrees. This is unacceptable that I had ~6cm less wiped from the drivers side.

b) The material was too soft. Somehow the VW material is much harder. Even though I used torque wrench to tighten the motor bolts. I realized one bolt was just compressing the metal holder!

The issue is perhaps also because the 3rd party manufacturer wanted to make a somewhat square slot for this specific bolt. I guess they wanted to leave a higher error tolerance because you can adjust the motor using this space a little bit.

c) The original gromments between wiper base and car body are tough EPDM rubber pieces. With 3rd part wiper the gromments were very soft like jello and I could compress them to few mm using my fingers! I imagine it won't give much stability to the wipers and probably useless when they are so soft.

d) The original metal bushes which go inside grommets are shorter. The shorter length bush and harder grommet make the original VW part more stable and less wobbly. In the picture below, the original part is on the left. Topran part is on the right.

Although the topran grommet is also slightly taller, it is much softer so it does not achieve same characteristics as the VW grommet.

6b- Install Geniune VW Replacement Wiper Base/Mechanism

The genuine VW wiper base mechanism (1J1 955 603 B) comes with only 2 gromments and no bushes. So you will need to order 1 more grommet (701955754) and 3 bushes (701955756). While doing that, I also ordered 3 new bolts with collar (N 0143441) to attach wipers to body. The original bolts had washers and new version apparently has a collar. I ordered a crank arm (535 955 121 A) just to make sure that I have everything in case if I need and assumed the crank arm ball could be worn slightly over the years.

I also ordered 3 bolts to replace motor mount bolts N 90305302. This was apparently superseded and replaced with N 90305304 which is a hex collared bolt. However I hit a wall there because apparently VW also changed the design slightly. The crank arm was slightly lower and the bolts with collars were slightly taller and in combination it would not fit properly.

As you can see, original arm (on the left) has a larger gap for screws and also the ball joints are higher.  The arm itself is also thinner.

Here I press the end base flat on the table so you can see how they sit in their final position. The original arm (on the left) sits slightly higher.

Here you can see that the combination of new arm and new screw does not work well. Here it actually fits barely but scratches the screw and arm.

I had two choices, use old arm or old bolts. I liked the crank arm being little lower, because the ball joints were connected in a slightly awkward angle in the original arm and this makes it better. So I decided to use the older motor mount bolt/washer combination which gave a good clearance to the arm. This combination is not as high as the collared bolt.

Assembling Linkages to Crank Arm

Used a generous amount of molykote 111 silicone compound on rubber bushings. I installed the linkages to the arm first. Because once the arm is on the motor, it is difficult to fit the bearing puller to pull the linkages in. I have carefully pulled in both of the arms to the ball joints of the crank arm.

Assembling The Crank Arm

Important: Before removing the original crank arm, you must mark the position exactly. or you will have troubles setting it up later. I did it double to be sure 100%. First I have rotated the arm to a position which could be replicated easily with new arm. Second, I have painted an arrow parallel to the crank arm on the drive shaft.

You will need the bearing puller to remove the arm without rotating the shaft. I was very careful to not to change the position I set. After that, it is a matter of putting the new crank arm on the shaft and carefully tightening the nut to 20Nm.

Assembling The Motor To Wiper Base

Since the linkages are already attached, you need to move them first through the hole on the wiper frame and then tighten bolts of the motor. Luckily the hole is more than large enough to easily fit everything. The tightening torque is 8Nm

Assembling The Rest

Now you can inser the other sides of the linkages. Again, I used the molykote 111 silicone compound  on rubber/plastic parts and also used the ball joint tool again for inserting them.

The driver's side linkage goes below the passenger side linkage (at least on LHD vehicle that I have)

As can be seen in the picture above. The driver's side goes over the drive shaft backwards in resting position. This is important, because it gives a more straight connection to drivers side linkage which should provide better connection. As the driver's side wiper is larger, this would improve the linkage life.

Also, after installing the motor/frame in position run wipers once from inside the car and let it come to rest position. Make sure that all the arms are lined up as seen on the picture above. Otherwise it would mean that you made a mistake somewhere.

Now you can go backwards and do reverse of the removal for the wiper frame/base. I cleaned the wiper motor connectors with contact cleaner and then used contact grease on them before installation just to make sure that it lasts forever.

The tightening torque for wiper frame/base to car body is only 5Nm!

Assembling Wiper Arms

If you forgot to install the water deflector. Do it now! The wiper arms should be installed with 25mm +/-10mm from the water deflector. The distance is measured from the wiper ends as seen in the picture below with mark A

The wiper arms should be torque tightened to 20Nm.

I have first tightened the arms just enough to adjust the position and made sure that they are at correct position before tightening to torque. Because once it is totally tightened, it is difficult to remove and re-adjust.