Brake repairs -- hydraulic side

Capt. Mike

Overhauling Vanagon brake master cylinder

Old age has caught up with me & Volksrat. At 150,000 I found the dreaded drip on the floormat. I had replaced the clutch master cylinder a couple of years ago, so surmised it was time for the master cylinder. Yep! Not major damage as I change fluid every 2 years, but just old age starting a leaking seal.

R&R is not covered very well in the Bentley. So here's what I finally deduced as the best way.

Remove the shroud under the steering column -- 2 Phillips head screws and a spring clip. Chances are it's got fluid in it anyway. Mine turned out to be cracked and the part number on it came up invlaid in the VW computer. Actually, the number was good, but you have to add "01C" to it because it's black; then the computer can find it. Must have had some other color in some market. About $60.

Remove the instrument cluster shroud -- basically rock towards driver using the finger grips in the edge near the windshield.

Disconnect the speedometer, headlight warning & brake filler cap wires. Disconnect multi-connector bottom right side. Remove the switches. Vw says remove the wiring connections first. I had to for the headlight switch (switch can remain in pod) but could just pop the whole switch for the rest just as easily. They are held in with two spring tabs -- one each side. Takes skinny fingers.

Remove instrument cluster -- 4 Phillips head screws. Have magnet at hand so you don't drop into the wiring mass below.

With cluster removed, disconnect both master cylinder switches -- you can reach up through the bottom for the one nearest the windshield.

Remove as much brake fluid as possible. I prefer one of the large syringes with a little rubber hose -- pays to have a friend at a hospital. It let me fish it through the partition and get about half the secondary reservoir, too. Place rags underneath the cylinder and all connections. Remember, brake fluid eats paint!

Disconnect soft line to clutch master cylinder. This is difficult; the special hose gripping pliers now available help. Replace if hose has hardened, split or end is 'cauliflowerd' or unraveling. Hold end out of way with wire tie or carpenter's clamp.

Remove two metal brake lines; 11mm flare wrench so as not to damage this soft tapered seal nut. I had two plastic plugs from my collection of removals to plug cylinder holes. Important as there is still a lot of fluid left in the cylinder. You can also get plug sets at the tool display rack of most auto supply stores.

The cylinder is held to the booster by 2 13mm lock nuts. Remove nuts. A flex socket or 'wobble extension' helps. Pull cylinder and reservoir clear.

Remove reservoir by rocking to side. Remove and discard reservoir-to-cylinder seals. They are NOT supplied with kit -- purchase separately.

If replacing with new master cylinder, it should come with new grommets and P/B booster seal. If not, purchase new, and skip overhaul steps below.

Removal of old piston assemblies is difficult. Remove circlip and pull guts out. Unfortunately, the washers and plastic discs catch in the circlip groove and it gets to be a battle. Since the parts are not saved, it's OK to put exposed piston in vice. However, avoid prying that might damage cylinder wall. I was eventually able to get mine out by holding piston in vice, and tapping flange with plastic mallet; reversing a few times until it cleared. The rest of the primary piston assembly then came out cleanly. Remove the stop screw to remove the secondary piston assembly.

Check interior bore and hone if required. Requires special cylinder hone and some skill --if in doubt, take to a shop. If major scratches, pitting or rust, replace whole cylinder or send to White Post for resleeving (see White Post topic in Mechanics > USA> Antique restoration . . .). It must clean up smooth as glass.

The replacement kit comes preassembled. Remove from tube, coat seals with supplied bore paste and insert secondary piston assembly. Reinstall stop screw with new seal (supplied).

Install primary piston assembly. This requires gentle working with non-sharp tool to work piston cups into cylinder and past circlip groove. A piece of plastic about stiffness of a credit card is fine.

The next difficult step is holding piston in under tension while you work plastic disk and washer down clear of circlip groove and insert circlip. One of those task where a 3rd hand would come in handy! Anything less than 4 "Sproing -- Oh crap!" is doing good.

Replace reservoir to cylinder seals and reattach reservoir. Insert new seal between cylinder and booster (supplied); reattach with NEW lock nuts. Torque to specs given in Bentley.

Reattach metal lines with flare wrench and clutch master cylinder hose. Refill with new DoT 4 fluid. Bleed system. Reattach switch connectors.

Bleeding the system will be very frustrating. You have introduced air at the highest point and it takes a long time to work through to the bleeders in the wheel cylinders. Have 2 quarts of fluid on hand. It may take 2-3 tries to get the air worked through. Don't forget to bleed the clutch slave cylinder until it also runs clear. Clutch bleeding is described on the site in it's own topic.

Reinstall instrument cluster and shrouds. You can usually put in place, hook up harnesses and test all functions before reassembly.

Don't be suprised if you have some spongyness and have to bleed another time after a good test drive.
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New member
I just replaced the entire hydraulic brake system on my 84 Westy. I replaced both calipers, the master cycliner, both wheel cylinders and all four flex lines. I also did the clutch master cylinder. I also replaced drums, disks and wheel bearings. It took most of weekend, but as the vehicle is looking at being 20 years old this November, I thought it was due.

And how. Although I had never noticed any brake fluid leaking, when I disassembled the wheel cylinders in the rear, there was fluid in all four boots. The amount of leakage wasn't much and it mixed with the brake dust to form some sort of goofy splatter putty that was all over the inside of the backing plate. Also, I found the beginning of a leak on the left caliper. (And inside the clutch master cyclinder boot.)

The process was time consuming, but not difficult. As Capt. Mike says the worse part is removing the instrument cluster to get to the master cylinder. And the rear drum brakes are a pain getting all the parts and springs back together. All of the parts, including new rotors, drums and rebuilt calipers cost about $400 from two various online parts houses. The disks were $52 each and were genuine ATE.

Capt. Mike in these posts has the only really valuable instructions for removing the master cylinder.

A couple of other hints. When working on the fronts, make sure to turn the steering wheel so the front wheels are pointed in the opposite direction of the side you are working on, other wise there is no room to move a wrench on the short hard brakeline that goes into the caliper.

The Bentley mentioned something about a lever on the brake equalizer for bleeding. As mine didn't have a lever, I didn't worry about it.

Removing the rear drums is a pain. Bentley shows removal of the rear axle castle nut. This is not necessary, but I can see the shop doing this to avoid having to get those drums off. They are rusted into place. As Capt. Mike says, back off the adjusters, but go beyond where they simply allow the shoes to pass below the ridge. Back them off an 1/8 of an inch more. Then put Liquid Wrench (or equivalent) around the point where the drum meets the axles Then using a small sledge, bang the drum around forward, side to side, backward -- what you're trying to do is break that rust seal. Finally, using only a regular size blade screwdrive, use it as pry bar between the rear shield and the drum to put some outward pressure on the drum. NOT TOO HARD. What you want is tension. You are NOT trying to pry the drum loose. Then, using the sledge, bang the drum right below where you have the screwdriver. It will move out a little. Then rotate the drum about 20 degrees and do it again. Repeat. It will still take about 30 whacks to get it all the way off.

Removing the flex lines was difficult because they were so rusted. I ended up destroying and replacing three hard steel brake lines, but all my flex lines were showing signs of cracking.

As this was a compelete redo, I bled all the brakes three times - once with a vac system and twice the old reliable way with jar of liquid and clear tube.


Help, hot brakes

100 miles into a 3600 trip, we pulled into the first rest area,,, Someone has hot brakes Susan said, not us as I felt around each wheel. Spoke too soon as it turns out. The right front wheel was so hot you couldn't touch it, the spindle as well. Smoking like a Peterbult on wolf creek pass, smelling just as bad. I called AAA and they towed us back to our home shop. Mark and Peter worked late, having a caliper on the shelf, they dropped the new one in and we were on our way, (we decided to drive the 10 miles home and start over again tomorrow). Stopping grocery store, I noticed the same smell. Sure enough the right front was blistering. (I was able to get it unstuck by pumping hard on the pedal). there is no pull to right or any other indication that it is sticking. Two questions, 1, does anyone have any idea what might cause this sticking? The brake fluid was changed 18 months ago, the brake lines were replace at the same time. The only thing that I can think of is there is a defect in the brake line. The other question is,, is there a possibility of damaging the bearing because the spindle got too hot. (86 Syncro) I'm back in the shop at first light, hoping to solve this so that we can get on the road tomorrow.

Thanks for any and all ideas

Capt. Mike

From a hydraulic point of view, the piston not retracting is possible due to trash in the line (acting like a flap valve where it enters the caliper) or a defective/disintergrating line that is swelling shut. The high pedal pressure can overcome it applying, but the removal of pressure doesn't allow it to pull back since there is no retraction force.

More likely is a mechanical problem (own topic) -- the caliper sticking. With a floating caliper, this can be caused by the sliding pins in the brake carrier (Bentley 46.5) being damaged or corroded. Had it happen on my tow truck just this summer. The front bearings on a syncro are sealed; if you haven't lost lubricant and there is no sign of noise or drag, you are probably OK. Overhaul your calipers as a precaution anyway. Polish and lube all of the sliding contact areas. Check your pads -- new pads often rub. I polish the slinding contact areas smooth as a matter of routine.



thanks for your reply. The pins were and are free, the pads are free. I have to conclude that the hose has gone south even though it is less than two years old. We'll replace the hose and give it a thorough test drive. If that doesn't fix it then,,,,



Replaced the hose, still no fix,, Finaly we replaced the rotors and pads on both sides. The rotors were quite rusty and pitted, and since we were grasping at straws at this point,,, Things are fine now. The conclusion that the best minds could find is that the combination of pitted rotors, and rust on the pad, caused the pads to stick in the carrier. In retrospect we probably didn't need to do the rotors, but since I am now two days late on a transcontinental trip, I fugured they should be the last rotors I ever have to buy for this car.

The general feeling amongst us all (the mechanics from Harmony Motor Works, Bellingham, Wa., can't speak highly enough about them) is that since my syncro is a road car and not a daily driver, and I am very easy on brakes anyway, this is the cause of all my problems. I drive 20-30,000 miles a year, but it is all road miles, no city traffic, no stop and go. The pads had at least 50k on them but they were nearly as think as new. I guess I will have be a little harder on them now and again. Once again thanks for the help Mike,



New member
1984 Westfalia

After a little more than a month, I wanted to report that the ceramic disc brake pads I put on the Vanagon Westy seem to have improved the braking considerably. I say "seem" because I also replaced everything else, so it's possible that the whole brake system is performing better than it was. I am the third owner. All repairs previous to me seem to be done at the dealer, so I assume the previous brake pads were all OEM.


New member
k ...not sure what thread to put this in but here goes, n move me if ya need to. the rear brakes of my 81 westie squeek, actually i think it's on one side, the passenger side. seems to be worse in the rain and cold. goes away (mostly) after it has braked a bit. got em checked and cleaned recently and here it is back again after 3 weeks. looked in the old repair bills and noticed this repair more than once. when i brought it back to the mecanic he said...rust, it's rust, been raining so much lately. but today it's windy and rain and still squeeks. so what is this, unique to my westie passenger side or....what....smiles here. thanks for a great site Capt Mike, sure is appreciated.

Mike Robinson

New member
Nick -

I am with you - same problem, the first brake of the morning is LOUD then everything quiet for the day, I am sure some days it does not make to noise on the first brake but it seems especially bad if not driven for a week. I recently had to go through the BC saftey inspection and the brake linings were fine, the quality of braking is ok.

Love to know what it is.


'82 Westy diesel

pascal giasson

New member
I have a two year old master cylinder that is leaking very slowly from the rubber seal between the brake fluid tank and the master cylinder. It is only the seal closest to the front that is leaking. Is there anything internal that could be causing the leak or should I just try to replace the seal? Thanks

'84 Westy

Capt. Mike

The tank-to-master cylinder grommets are independent of any seals in the master cylinder itself. However, if this lightly-stressed seal is leaking, it may be indicative of general old-age or pending failure of the master cylinder. It may be time to consider overhauling (r replacing with a reman) the whole unit. Those gromets can be quite difficult to replace 'installed'.

pascal giasson

New member
I changed the two seals between the brake fluid reservoir and the master cylinder. I did it all in the Westy ( a little tricky, but I did not want to remove the master cylinder just to replace those seals). So far no more leak. I'm guessing that the previouse owner took the old seals out of the old master cylinder and reused them in the new master cylinder. The old seals still look good but not good enought to make a leak tight seal.

Capt. Mike

Not on my Westy, but applicable. I recently had a brake failure on my big tow truck. I was lucky -- see "Warning light" topic this forum. The cause was a leak in the fixed metal line running from the front to the rear brakes. It was in an area in the frame rail hidden by the fuel tank. Extreme corrossion on a 9 year-old Southern truck that has had meticulous pressure washing of the undercarriage the few times it's been in snow.

We found a couple other metal brake lines beginning to show corrossion as well. I had bought the Dodge for the Cummins diesel power package -- I've long said the Dodge-made side is a piece of crap and that's reinforced every day. Naturally, Dodge has discontinued the part, so it meant custom fabrication from brake line stock. $410 later I have a new, undercoated line.

When your maintenance schedule says "inspect brakes", it doesn't mean just count the calipers or peek at the pads. It even means more than checking the rubber hoses. INSPECT your metal lines, especially where they get hidden from normal view. Use those dental and inspection mirrors; use the little remote wand flashlights. Whatever it takes, but DO inspect them . . . routinely.

There are a number of good undercoating and rust preventatives on the market. 3M's Rubberized Undercoating is as good as the factory 'tar' coatings. LPS#3 is a good renewable one with about a year's protection that is almost clear. See the SUPPLIERS forum.

Capt. Mike

Transferred to consolidate same topic.

siva Junior Member Posted September 09, 2005 05:40 AM


Westy details: '83 air cooled vanagon westy 2 liter

I've been driving my westy all year with no problems. When I put it on the road in the spring, I had to get the front brakes done. Apparently the calipers were seized, so the calipers and brakes where done at the same time.

Fast forward to today. We were on a camping trip, and were driving down a very very steep long hill. Half way through I could smell something burning. Then my brake pedal "pressure" started to drop and the brakes degraded.

By the time we reached the end of the hill, I was pulling on the emergency brake and coasting in second gear because most of the brake performance had dissappeared.

The smell seemed to be coming from the front end, and as I had a problem the year before with brake fluid leaking, I figured it had something to do with that. So I pulled the dash cover off (in front of the steering wheel), but couldn't see any smoke or anything.

I waited awhile, and decided to try the brakes again, and they seemed to return to normal, although I wasn't willing to try going down that hill again!!

Any suggestions?

icarus Super Member Posted September 09, 2005 07:54 AM

I know MIke will move or delete this because it is a mis-post, but you bring up something that everyone should know.

It sounds like you overheated the brakes, particularly the fronts. A couple of things that you spoke about concern me greatly. If you are on such a steep grade as to over heat the brakes, you MUST shift down, even into first or second gear. A westy is a heavy vehicle and to make the brakes do all the braking force is dangerous! The old truck drivers rule is, you go down a grade in the same gear you go up in.

The other think you mention is "coasting in neutral" Why in the world would you coast instead of shifting down. Also pulling on the hand brake only activates the rear shoes (and if I'm not mistaken 1/2 the rear shoes) so that your braking force is less than 1/4 of normal.

I suggest that you look over the brakes carefully now, to make sure that you haven't damaged pads, glazed shoes, or cooked calipers or brake fluid.

If everything checks out I suggest you do some practice decents using downshifting. When you are at the top of the grade find the gear you would use to go up it, let the car run down, using the brakes only to keep the rpm in check. If you have to use too much brake, you should be in a lower gear!

Drive safely!

Capt. Mike

Icarus very tactifully points out what was a dangerous lack of good sense. Your owner's manual warns you about continued driving after a brake failure. You SHOULD have pulled off right then and allowed the brakes to cool, besides a full inspection.

Read the Bentley and understand the principals behind hydraulic brakes. There are several topics on brakes in this site, such as the mechanical side of repairs, power brakes and a discussion of brake fluids in the TIPS forum. Read the Guidelines and use the search engine.

VW requires brake fluid changes every 2 years because the fluid deteriorates and loses boil point. VW also requires DoT 4 fluid, not the cheaper DoT 3 used by most shops, for the higher boil point. When you overheat brakes, you cause the fluid to boil into a gas, especially if it has any moisture (brake fluid is hygroscopic), and gas compresses = loss of brakes.

Brakes get very hot. Even mild use on a single routine city-speed stop pushes temps into the 300°F bracket. Heavy use, lack of cooling between, and conditions such as a steep hill can push the temperatures to the point of causing the rotors to actually glow red-hot from heat. What you smell is that heat and hot linings. Of course that heat also transfers eventually to bearings and seals, leading to possible bearing failure or other damage. Overheated pads can become unstable and disintegrate; overheated rotors can warp or lead to cracks.

Examine your driving habits. As Icarus points out, you should have been in the lower gear all along. Also, on hills, you should pump the brakes giving them cooling time between. Also, you should brake down to a slow speed to give the brakes cooling time before needed again rather than just 'riding them down' to the speed you want. Go well below and then give yourelf time in that low gear to build up. Disc brakes do cool quickly if given time between applications. There is no shame in stopping for brake cooling -- it's far better than the one unplanned BIG SUDDEN STOP.

I'd also question the recent work. Did they use name brand DoT 4 fluid; did they use OE or OEM parts? Cheap aftermarket pads may not handle the heavy (5,500 lb) weight of a loaded Westy, whether they "fit" or not. If you had major problems before, the fluid should have been changed out again shortly after to be sure the system is adequately flushed, then return to the every-2-years requirement of VW.

Finally check the proportioning valve; are you getting the designed apportionment between front & rears? The rears are great brakes, even though the older shoe design. They should carry their fair share!
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Capt. Mike,

You bring up an interesting and ongoing debate regarding pumping the brakes. In the old days of drums all around, the brakes had no oppurtunity to to cool as long as the shoes were contacting the drums so that pumping gave the drums a rest and an air space. With front discs 80% of the rotor is "in the air" all the time and therefore gets cooling air. The arugument is is it better to do coninuous light braking or intermitent harder braking? I myself tend to do short, harder braking with longer off brake periods.

Truck drivers are admonished not to pump there brakes, mostly because of the danger of exausting the air supply.

The question is, does anyone know what the science of this all is? I tend to be very easy on the brakes. I get 100,000 miles or more on a set of pads.



New member
The other think you mention is "coasting in neutral" Why in the world would you coast instead of shifting down.

Hi Icarus,

I said I was coasting in second gear. My use of the term "coasting" here was misleading. What I meant was I was letting the gear slow the vehicle down, while using the emergency brake to keep the RPM down.

Thanks for all of the info though, as I now realize the error of my ways. I started out too fast (not knowing the area), and didn't use the gear to begin with to slow the vehicle down.

From now on I'll be very careful when driving down steep hills (using the gear and pump action to manage it).

I haven't used the Westy since, and I will take it into the shop right away to get it checked out.



New member
1990 Westy/Girling calipers...I rebuilt the calipers/fronts. All was well on one side- but on the drivers side, the caliper piston was TIGHT and kept pinching/cutting the dust boot (drats- $15 for each kit).

I tried all the tricks, large C-clamp, wiggles, extra wet hyd. fluid. The piston just would not push into the caliper with the lip of the dust boot in place. Finally I gave up. Ideas? Yes, I had removed the res. cap and removed the 7mm bleeder bolt (new from Scwab- the old ones were rusted crud-shut).

So for a hydraulic repair- how do ya git the piston back in? PS yes, Bentley says to do what I did).


New member
Spongy brakes

1981 aircooled, manual trans. My brakes were a bit spongy & the clutch occasionally didn't release all the way. I can not find ANY fluid leaks and have searched everywhere. I added maybe 2 teaspoons to the master cylinder 500 miles ago.

Today I bled the whole system. The clutch bled "right"- some brown fluid and bubbles clearing up to a steady stream of clean fluid.

The brakes refused to ever put out a stream, I got 50% air in every vacuum suck. Switched to a partner pump and hold, same thing. Brakes are probably worse now than when I started. What's going on?? PS I was very careful to keep the reservoir full during all this. I burned through 3 12 oz bottles of DOT 4.

1. Is clutch first the proper way or should I start with brakes?
2. Can there be some kind of internal air suck in the system (grommets between reservoir tank and master) that's allowing air to enter, but does not leak fluid?

I noticed that, while the systems are connected, the clutch actually take its fluid from the reservoir via a rubber hose so therefore is independent of the master.

Any suggestions welcome!
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