Squeaky Brakes on First Pedal Use

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sped372
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Squeaky Brakes on First Pedal Use

Post by sped372 » Tue Jan 27, 2015 8:00 am

(This is on our 1970 Bus)

Short Backstory:
Replaced everything in the rear about two years ago, replaced everything except the drums themselves in the front before the start of last year's camping season. New shoes, cylinders, adjusting stars. Cleaned everything judiciously and did the cross-hatch sanding technique on the re-used drums up-front. 50/50 moly and anti-sieze on the stars. Trouble began last year, which (coupled with my ears) tells me the issue is up front.

Symptoms:
On first application of the brakes they grab and squeal... real bad. If you can ever-so-carefully, gingerly and slowly, apply the brake pedal to slowly and barely stop on the first use there are no symptoms and then the brakes are good to for the rest of the journey. It's like the 'seat in' or something. Even if you let them squealgrab bad (which is embarrassing to say the least), they won't do it again after the first use. I'm not sure how long the bus needs to sit parked for the squealgrab to come back, but overnight will do it for sure. It does not seem to return while you're driving, even for an extended highway jaunt with minimal brake usage while underway.

I want to get this cleared up before spring rolls around. Does this sound like an 'oh duh' obvious fix? I can pull the drums but I am worried I'll just see nothing out of the ordinary and not know what to fix!
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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Re: Squeaky Brakes on First Pedal Use

Post by Amskeptic » Tue Jan 27, 2015 8:52 am

sped372 wrote: On first application of the brakes they grab and squeal... real bad.
Remove drums. Look for any evidence of grease contamination on the linings.

a) you were sloppy, bad pig

b) bearing grease seals leaking?

c) wheel cylinder leak? look for liquid in the boots,
I DON'T CARE IF THEY'RE NEW, :L :cyclopsani: :cyclopsani: K!

(if contaminated, you can clean the drums and shoes with brake cleaner and sand paper and paper towels until they are dry and clean again.
zabo sez, don't forget! keep the dust down! you can die a painful death of mesothelioma!

d) if none of the above, you have crap-for-linings that need a little heat to greet the day, resand drums just before you install high quality shoes.

e) no, I do not know the difference between "good" linings and "bad" linings until I inspect the box they came in

Does your bus stop nicely?
Colin :geek:
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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sped372
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Re: Squeaky Brakes on First Pedal Use

Post by sped372 » Tue Jan 27, 2015 9:12 am

Bus stops very nicely (with the exception of that first squeakgrab). I was super duper careful and particular, so I don't think I contaminated anything. I will pull the drums and inspect. I'm confused, say I find something has leaked and the shoes are contaminated, I sand the shoes!? Purchased everything from Wolfsburg West, was "supposed" to be the good stuff.
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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Re: Squeaky Brakes on First Pedal Use

Post by Amskeptic » Tue Jan 27, 2015 9:32 am

sped372 wrote:Bus stops very nicely (with the exception of that first squeakgrab). I was super duper careful and particular, so I don't think I contaminated anything. I will pull the drums and inspect. I'm confused, say I find something has leaked and the shoes are contaminated, I sand the shoes!? Purchased everything from Wolfsburg West, was "supposed" to be the good stuff.
Well . . . yes. You clean them or you replace them.
I like to be frugal and environmental and practical, so I let
a) carb spray lift grease
b) soap and water lift brake fluid
out of lining material. John Muir used Coleman fuel and a match . . .

Let us know, mr superduper, if you have contamination. The new world does not care about super clean super thorough. I have seen Varga brazilian wheel cylinders piddle all over your careful work after three lousy months.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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sped372
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Re: Squeaky Brakes on First Pedal Use

Post by sped372 » Tue Jan 27, 2015 10:14 am

I even sprang for the German cyls... but maybe that doesn't mean much any more. Wonder what I'll find.
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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Re: Squeaky Brakes on First Pedal Use

Post by wcfvw69 » Tue Jan 27, 2015 8:14 pm

How ironic that I read the exact symptoms my 1970 bus is giving me. Front brakes. Squeeks upon first brake pedal application and does not squeek again after the first time. Same situation. All new (good quality) parts, drums were turned, etc.. Was torn down for a second visual inspection and everything passed. I even dabbed an ever so slight amount of lithium grease on the backing plates where the steel of the shoes rub.

I'm going with surface rust on the drums (not a daily driver) that is wisked away after the firts application. Yes, that's it!
1970 Westfalia bus. Stock 1776 dual port type 1 engine. Restored German Solex 34-3. Restored 205Q distributor, restored to factory appearance engine.

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Re: Squeaky Brakes on First Pedal Use

Post by sped372 » Wed Jan 28, 2015 6:17 am

Where'd you get your shoes?
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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Re: Squeaky Brakes on First Pedal Use

Post by wcfvw69 » Wed Jan 28, 2015 9:49 pm

sped372 wrote:Where'd you get your shoes?
They were on the bus when I bought it back in June. They were new and the drums were freshly turned. I just had to change some wheel cylinders and the rubber hoses.
1970 Westfalia bus. Stock 1776 dual port type 1 engine. Restored German Solex 34-3. Restored 205Q distributor, restored to factory appearance engine.

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Re: Squeaky Brakes on First Pedal Use

Post by sped372 » Thu Jan 29, 2015 6:18 am

Interesting. Well I likely won't get to this job for awhile but wanted to do some preliminary research while it was on my mind. I will report back with my findings.
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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Re: Squeaky Brakes on First Pedal Use

Post by wcfvw69 » Thu Jan 29, 2015 6:48 am

sped372 wrote:Interesting. Well I likely won't get to this job for awhile but wanted to do some preliminary research while it was on my mind. I will report back with my findings.
Please do. I'd be curious if you isolate the cause.
1970 Westfalia bus. Stock 1776 dual port type 1 engine. Restored German Solex 34-3. Restored 205Q distributor, restored to factory appearance engine.

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Re: Squeaky Brakes on First Pedal Use

Post by Amskeptic » Thu Jan 29, 2015 8:18 am

wcfvw69 wrote:
sped372 wrote:Interesting. Well I likely won't get to this job for awhile but wanted to do some preliminary research while it was on my mind. I will report back with my findings.
Please do. I'd be curious if you isolate the cause.
I will be anxiously awaiting your report as well.

There is a little bit of tea leaves reading to all of this.
Do not be "cursory" (today's Itinerant Air-Cooled word-of-the-day) in your inspection, be thorough.

For example, you are performing a biopsy when you sand a little section of what may look like perfect braking lining, and you note with amazement that the sandpaper picks up a black greasiness that just did not look like it was there initially.
Then you wetten a paper towel with carb spray or brake cleaner and note with even more horror that the damn shoe seems to have been alchemically making grease in what looks like a nice dry drum. What is supposed to happen is that the shoes are designed to lay down a glaze on the drum, it is part of the composition of the lining material. This glaze is a rust inhibitor and a metal polish. All linings have their own favorite recipes. Some like to throw carbony black dust, some like to throw a rusty looking reddish dust, some throw very little dust but eat drum metal, etc. If there is a little bit of brake fluid or wheel bearing grease, you no longer get dry dust . . . you get mud. :pale:

I will be checking Chloe's front brakes and packing the wheel bearings (third time since I have owned the car) today and tomorrow. If anything looks similar to what we are looking for in your case, I will post photographs. Please do sand a little chamfer on your shoes at the leading edges (where the drum rotation first greets the shoe)
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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sped372
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Re: Squeaky Brakes on First Pedal Use

Post by sped372 » Sat May 09, 2015 1:21 pm

Well, good news? Pulled the front drums and everything was dry dry dry. There was a dime-sized dark spot one one shoe, it came off with two light scuffs of sandpaper. So, now what? I did the crosshatch deglaze procedure (looking at them I think I may have forgotten to do this before) and put everything back together. Test drive. No squealgrab! Hopefully it wasn't a fluke test drive, I will report back if it redevelops.

If I am cured, was it the glaze or the tiny dark spot?
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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Re: Squeaky Brakes on First Pedal Use

Post by Amskeptic » Sun May 10, 2015 8:07 am

sped372 wrote: If I am cured, was it the glaze or the tiny dark spot?
Yep.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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