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Sun Mar 12, 2017 6:10 pm

I have had a brake leak into my floor boards for the past month or so. If you look at the discoloration on the floor mats what is the likely source? Clutch master cylinder, brake master cylinder? The leak is not obvious as I look up and under and over. This is from a 1980 Vanagon. thank you for your help.

Sun Mar 12, 2017 6:21 pm

Happily, it should be easy to I.D. Just remove your instrument binnacle cover, take a bright light and examine where each brake fluid line connects.

Be gentle as to the wiring back there in terms of leaning on or pushing on things.

Sun Mar 12, 2017 6:57 pm

Pump the pedels also if difficult to trace, flowing fuid will be more visable, bright light helps a lot. also remove soaked carpet and wash off with lots of water, use rags, towels to mop up any traces of spilled fluid from other floor matts, and vehilce floor, rinse or wet mop over all ex
osed areas several times, wipe down with water wet towels all other contaminated surfaces. brake fluid is corrosive to many metals, and eats thru many paints, including automotive paint, It is water rinsable, so mop up as much fluid as you can, the mop over with water to rinse.

keep the fluid off your skin, wear rubber gloves, It can be absorbed into the skin, yuck! Dont touch anything with brake fluid covered gloves on the car. wear glasses, Brake fluid can give an extremely bad and painful eye burn, dont let any brake fluid spill on the instrument cluster, it will strip the markings right off.

good luck

Sun Mar 12, 2017 7:27 pm

Very likely the clutch master cylinder. When the seal fails, each time you work the clutch a little fluid gets expressed. Where you're showing it on the floor is exactly where it winds up.

To test this, reach up from the pedal set until you find the clutch master cylinder and feel around for the loose fluid. If you find some there, it's probably the source. To double-check, pull the binnacle off (careful of the wires and especially the fragile plastic instrument-cluster leads). Feel around the bottom of the reservoir and at the brake-line unions. If it's dry up top, the source is the clutch master cylinder.

Changing this out is difficult because of access, but do-able. Pulling the feed hose from the reservoir up top to the cylinder is hard-to-impossible without breaking the plastic tip off the back of the cylinder; be prepared to buy a spare hose or go get a new one to replace it (got mine from Van Cafe).

Keep that rubber mat in place, it's great for keeping the fluid off the carpet.

If the master cylinder is failing, the clutch slave cylinder is not far behind.

Mon Mar 13, 2017 9:20 am

Rarely is the brake master cylinder going to leak externally. When it does, it will go into the brake booster and eventually gets sucked into the engine. Brake boosters seals are brake fluid proof so there is little chance of damage. Suck any fluid out if you see any. I would also check the reservoir seals to make certain they are dry to the touch.

So that leads to the clutch master cylinder. That is something you need to resolve fairly quick because if you loose enough fluid, you will not have a clutch and it can be a chore to drive it would a working clutch.

If it was me, I would just replace all both master cylinders and replace the slave while you're at it. Understand how to bleed brakes because it seems to be a major issue on forums that people do not understand how to bleed them properly.

Mon Mar 13, 2017 9:43 am

As others have suggested, that’s quite likely a failing clutch master cylinder.

To confirm, as with most leaks, the best approach is to thoroughly dry/clean everything up in that area at the top of the pedals. Pump one pedal and, using a bright light, watch for leaks and trace them upward to their source. If nothing, then try the other pedal.

If it turns out to be the clutch slave, you may find this write-up helpful:
http://campwestfalia.com/vanagon-hydraulic-clutch-system-overview/

Good luck!

Mon Mar 13, 2017 2:08 pm

Many thanks everyone. I have the clutch master cylinder on order and will dig into it this weekend. Luckily I was in my driveway when I noticed the very low brake fluid level. I'll post what I find out. The write ups on Campwestfalia are terrific and very much appreciated!

Mon Mar 13, 2017 3:00 pm

GreenieSMU wrote: Many thanks everyone. I have the clutch master cylinder on order and will dig into it this weekend.

Hopefully you checked to make sure it wasn't something else (like the super inexpensive fluid reservoir O-rings) before you started ordering parts based on the guesses of people who can't see your van with their own eyes.

Mon Mar 13, 2017 3:59 pm

Yeah - guesses are great, if you're a good guesser.

The last time I had a leak like that it was the brake master cylinder. Easy enough to replace but you really should be sure about where the leak is before ordering and replacing parts.

People speak with such certainty then others chime in with agreement - all w/o actually knowing what is going on. Think of it as the Samba Psychic Help Line.

Check everything, in addition to the clutch master... brake master cylinder, brake light switches (2 of them), rubber connections where the reservoir plugs into the top of the brake master, hose to the clutch master, nipple on the reservoir where that hose connects and of course the various hard line connections.

One clue - if the leak is the clutch master the fluid level will not drop below the point where the hose to the clutch m/c connects on the side of the reservoir. This is so a leaky clutch m/c does not cause you to lose your brakes.

To test that you could pump and let it leak and see if the fluid level stops dropping once it is down to that level.

Tue Mar 14, 2017 8:27 am

All fair points. I will be doing a full inspection this weekend. I wanted to get ahead of the most likely repair. Again, the advice and suggestions are all very helpful.

Wed Mar 15, 2017 8:06 am

Finally got to work and found that the brake master cylinder was leaking into the brake booster and the clutch master cylinder was leaking as well. Parts are on order and I'll get sorted this weekend. Taking both mc(s) out was pretty straight forward.

Wed Mar 15, 2017 8:57 am

consider new hose on reservoir.

good luck

Wed Mar 15, 2017 9:14 am

How much of an issue is leaking brake fluid on all of the wiring that is there underneath the instrument cluster?

Wed Mar 15, 2017 3:59 pm

When changing out the brake and clutch master cylinders, once complete which do I bleed first? Brakes and brake master or clutch master? I am thinking bleed brake master, then clutch master, then all four wheels?

Sat Jun 01, 2019 8:57 am

This seemed like a decent thread to revive for my issue.

You're seeing the driver side rear wheel; drum brake. This must be brake fluid, correct?

Recent brake system work included:
New Van Cafe master cylinder
New GoWesty braided stainless hoses
Replaced passenger rear hard line
Replaced driver front hard line
Fluid flush

Any common leak spots that I should check?
Things to tighten?
Safe for a short outing with the fam, or get it addressed ASAP?
TIA.

Sat Jun 01, 2019 9:23 am

You don't mention rear brake slaves as being replaced. I would look there.

Sat Jun 01, 2019 11:38 am

A great thing about brake systems is that they usually give you some warning before catastrophic failure,

This is your warning.

Sat Jun 01, 2019 5:55 pm

So...rear wheel cylinder. Would it make sense to replace both?

I’ll heed the warning, and get this fixed.

Sat Jun 01, 2019 6:30 pm

I was about to say safe, but then saw "family" - no, don't risk your kids

Might as well do both wheels...

Sat Jun 01, 2019 8:10 pm

ELO78 wrote: So...rear wheel cylinder. Would it make sense to replace both?

I’ll heed the warning, and get this fixed. . This was the exact warning my ‘84 gave me while at work with it.
Brake pedal still felt decent, but would have gotten worse as the leak progressed.