Identifying brake fluid leak /changing rear brakes

[Moonwolf12]

I was told I had a rear brake wheel cylinder leak, using the brakes on the Vanagon we have to pump it some to come to a stop, it seems to be a slow leak because I've only had to top off the brake fluid once, couple of questions here:

How can I tell where the leak is coming from? Is replacing the brakes enough to fix a wheel cylinder leak? Changing the brakes seems doable for a DIYer, any tips for a novice?

Rear right

Rear left

Under the van

[syncrodoka]

Which rear tire has fluid slung on the inside? That is a sure sign of a leaky wheel cylinder.
Having to pump the brakes means there is air in the lines and the brakes need to be bled.

[vanis13]

[SCM]

[MarkWard]

It’s easy enough to pull the rear wheels and pop the drum off after you remove the two tiny bolts and have a look. If you can’t get the drums off, I’d find a shop that has specializes in classic VWs and cut your diy teeth on something else. Brakes is not one of those things you want to hope is correct. Sorry to be a tool.

[dhaavers]

^^^ Agreed, generally. I’m not a hardcore wrencher, but brakes was the first job I did when I got the van.

Your rear wheel pics show the end of the axle & CV boot inside the trailing arm, nothing to do with braking at all. There may be evidence of a leaking brake cylinder on the inside surface of the rear wheel (dirty, oily residue all around inside). If you’re lucky you might solve a leak by simply tightening the bleeder bolt & brake hose connection, both of which are accessible from the “back” side of the wheel where they come through the brake backing plate above the trailing arm.

Not as likely, but leaks could also be occurring at any hard line connection such as at the proportioning valve, at the rubber flex hoses, or there may be leaks from the hoses themselves…(shudder). Don’t expect any of those connections to come easily, they’re often rusted beyond recognition & susceptible to damage in that condition. Proceed carefully.

For most typical brake work you’ll probably need to be working from the “front” side of the wheel to access the wear items: shoes, drum & likely springs plus related hardware. Get the van up on good jack stands, take the wheel & brake drum off. Here’s where you’ll be able to see the actual brake cylinder directly above the hub. (PS: Do you own a Bentley manual?)

FYI: Here’s a borrowed pic of a nasty longtime-leaking cylinder:

…and here’s what you’d rather see:

So…go ahead and get in there. What do you see?

- Dave
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86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[zerotofifty]

A Do It Yourselfer who is even a little bit vague on which is the front or rear of the van certainly should have someone else work on the brakes. Until that is learned, I not recommend doing more than washing the Van. I say it is not ok to even drive the Van until at minimum you know the front from the rear
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Sorry About That Chief.

Give Peace a Chance.

Words to live by.

[dhaavers]

^^^ Career public school teacher here. My personal philosophy: “All can learn and improve.”

Wink emoji suggests a lighthearted aspect to your post, I’ll take it that way & expound a little…

The fact is, OP started here a few months ago with a new van & a long list, and has systematically been working through it, learning by doing all along. The purpose of the forum is multifaceted, but to provide guidance and encouragement is a main reason for my continued involvement.

I’ve seen that OP has been on the forum each of the past several days…perhaps another learning opportunity to ask for a check in on his progress <or> timeline. I know he’s provided closure on several other threads once problems are solved, I expect the same here when time allows.

Good luck, keep in touch, Git ‘r done!

- Dave
_________________
86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[zerotofifty]

[khughes]

If your mechanic 'saw' a leak, then it has to be on the backside (between the wheel/tire and the center line of the van) of the backing plate, or around the inside of the wheel where it goes around the drum. If it isn't leaking out there, there's no way short of pulling the drums to tell if there is a leak and someone may be blowing smoke.

OTOH, as brakes wear the "at rest" amount of fluid in the lines will gradually increase as the disks in front gradually have to reposition closer to the rotor. You'll see this as a slight decrease in master cylinder level - not a lot, and for sure not frequently at all. The brake shoes being out of adjustment in the rear will definitely cause a "low" brake pedal, and may need an extra pump to get them far enough out to contact the drums. The first pump gets them close, and the return springs don't have time to push that fluid back into the lines before your second pump so now you have a stiff pedal. The shoes fully retract before you need them again, and a'pumping you go again. Air in the lines will be a similar effect, although you should notice a spongy pedal, not stiff.

Take a look at your backing plates, both sides should be dry as a bone. If not, it's brake job time, shoes and wheel cylinders at the least, drums also very likely. May be machineable but...
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'86 Westy FAS GenV Turbo (Marvin)

[Moonwolf12]

[Moonwolf12]

[Moonwolf12]

[Moonwolf12]

[MarkWard]

Take a small screwdriver and pry each dust boot off the wheel cylinder. 2 cylinders, 4 boots total. Any dampness indicates the wheel cylinder needs to be rebuilt or replaced. Can you replace a wheel cylinder with the shoes installed? Yes, takes a little finagling. Wash the shoes and backing plates with soap and rinse with water to get rid of any fluid residue or brake dust.

[zerotofifty]

Once a shoe becomes soaked in fluid, it is toast, so get new shoes, replace both sides for even braking. always replace the shoes in left and right pairs rebuild or replace the leaked cylinder. Id be inclined to replace cylinders on both sides as the other may not be far from leaking.
measure drums , only machine if you have enough metal left on them with out machining past the wear limit. machine if deeply grooved, else reuse but scuff them. course sand paper will work

if hoses show signs of cracking, replace the hose
_________________
Sorry About That Chief.

Give Peace a Chance.

Words to live by.

[khughes]

[vanis13]

The OP follow-up is nice

Be discerning on the wheel cylinders you choose for replacement.... There is a recent thread with reading something like "ATE cylinders are CRAP"

FWIW, my vote is to replace only to rebuild the failed cylinder - one if the rain is that the replacements may be crap but also, that the other has proved working well and could last tens of thousands of miles more.... Though if you choose to rebuild, I'd rebuild both since not only is it cheaper, more importantly you will become intimately familiar with the cylinder so you know what you have.... And rebuild one at a time so if you screw it up, you screw up the already bad one and get to relearn w.o affecting the one that already works.

.....your approach and interaction styles make it easy to help you so thanks for that
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83.5 Westy with Subaru 2.5, 4 spd manual, center seat, COLD A/C on 134a!, Winter camp heated with an Espar B4 gasoline furnace

www.SuperVanagon.com - some stuff I make

[dhaavers]

Brakes are important, you’re doing good work…but just for a minute, let’s back up a bit.

You were “told” you had a leaking cylinder, yet the only symptoms you describe are soft pedal (requiring pumping to stop) and one instance of needing to top off the brake fluid reservoir. Now for the questions:

1) Soft pedal comes from air in the system, requiring a simple bleed. Have you completely bled the system? (Might as well Include the clutch line, if ya got one.)

2) From this end of the internet I see no obvious major leak from either rear cylinder <or> front calipers. Am I missing something? As MarkWard mentioned, you can inspect for fluid under the rubber caps on each cylinder…ZERO fluid present is what you want to see. Please check this & report back.

3) Rear shoes pivot at the bottom & only move due to the cylinder pushing outward at the top edge. Because of this, shoes typically wear more at the top…it’s normal. Is it worse than it looks in your pics? Perspective is a powerful force.

Sometimes ya gotta become like the child of Perry Mason and Tim The Toolman Taylor…investigate, then do the work!

- - - - - - - -

Unequal wear & dust from side to side could be several things:

A) Poor adjustment of “star” adjusters, &/or unequal adjustment from one side of the van to the other, or poor operation of “self-adjusters” once on the road. Not uncommon, these issues both provide regular forum fodder. Clean things up, install & adjust correctly and you should be in good shape for a good long time.

The self adjusters are kinda finicky…require complete disassembly, a really good cleaning and just a <touch> of lubrication on the threads before reinstall. They are also specific to the left/right side of the van so if you (or someone else) mix ‘em up, they won’t adjust nothin. If suspicious, check the star adjusters from time to time after some (thousands of) miles & make it right.

B) It’s possible the PO installed different types <or> brands of shoes on opposite side of the van. (PO’s be like that sometimes… ) If so, it wouldn’t surprise anyone if they wear unevenly. If you don’t like what you see, spring for a new matched set.

C) Unusual-to-uncommon, but also possible the proportioning valve is outta whack causing unequal braking on one corner. (Check everything else first before working too hard on this one.)

Weekend now…it’s a good time for quality van time! Keep in touch…

- Dave
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86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[Moonwolf12]