Odd rear brake behavior

[Ledbellyhead]

Called bus depot and they said they would mail the correct ATE, and send RMA for this one... it was drop shipped. Guess I'll be another week.

I did put a new hardware pack in the back with new springs and all.

It's been bled meticulously. I may have to shim it some with the new one, may have needed it with the old, but it was an auto zone replacement and after everyone's input I'm putting the best thing I can on it. I'm also going to do the WW Porsche 944 front disc when time allows.

I'm thinking that this could be the drums being warped like Sean said, but there is absolutely no pulse in the brakes, I can see how that could cause the shoes to shift and drag. I will take them to NAPA and see if they can turn them, they do have a slightly noticeable spot when adjusting them, but not what I would have considered a problem.

[Tcash]

For Vendor feedback. Please use the Buyer and Seller Feedback Forum.
The Bus Depot
Thank you Tcash

[SGKent]

were it me, I would jack the rear up before and after a trip to see if one or both of the rears are dragging. You can also use an infrared gun to see which is dragging and getting hot. Use the brake bleeder screw to see if releasing pressure causes it to return and stop dragging. If it does then the issue is hydraulic. If it does not then the issue is mechanical.

Also - if you are basing the dragging issue on HEARING a dragging sound, and an IR gun shows it is not getting hot from dragging then it is the drum rubbing on the backing plate and not the shoes. There are several fixes for that.

Typical drum dragging causes that I can think of:

Rubber lines rotted on the inside
weak return springs
return springs not connected correctly
blocked port on brake master
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[kreemoweet]

[Tcash]

To link to this post copy and paste

[SGKent]

on late bays the rod is adjusted between the pedal and booster, unlike many cars with boosters where the rod itself is adjustable. On early models the pushrod has an adjustment. Read Bentley Brakes and Wheels 4.1. Blocking a compensating port will keep the brakes from releasing.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Ledbellyhead]

[kreemoweet]

[Ledbellyhead]

I have checked the clearance that you speak of only by removing and re-installing the master and the feeling I was referring to was almost like you could feel it seat in the piston by pressing on it from the rod, you could feel the gap inside the booster, I studied those pictures hard a year ago. I have also tried to release on the bleeder with no pressure. When the correct master gets here and I install it, we will see. I want to do one thing at a time instead of everything so I know what the problem really was.

Checking with no o-ring and then replacing is a great idea, I did not do that.

Thanks everyone for the help!

[Ledbellyhead]

[Tcash]

No chastization here. If that's even a word.
It is only fair to both Buyer and Seller to use the Feedback Forum.
It also gives a prospective Buyer a good resource to use when deciding to do business with a seller.
No worries.

I added some information to my previous post above.^^^

Hope it helps
Tcash

[Ledbellyhead]

Thanks so much Tcash, I will check using this method as soon as it gets here, I didn't realize when I installed the other how important it was until it was bled, I may be able to install it upside down without removing the booster to check with a light. Then remove and bench bleed, and install and bleed again...

[DougB]

[NOVA Bus]

So just reviving this thread; I have given up on the WW "Throw you through the windshield" brake servo. It's not a good reproduction, period.

For replacement I located a well preserved used brake servo OE ATE spec for my '77 bus.

To review, the booster push rod (point) which nests into the brake manifold is NOT adjustable inside the booster itself, per Bentley the adjustment for the push rod pin can only be performed by adjusting the extension "tie-rod" link which connect from the front of the brake servo lock but to the brake pedal linkage.

Also Many posts on here regarding restoration options for original brake servos, it looks like there are still some good sources, but upwards of $200 to perform this repair.
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1977 Transporter / Weekender
- GE engine, L-Jetronic w/ hyd. lifters
- Brown Beige plaid P27 Interior (ED)
http:/[url=http://www.vw-mplate.com/mplate-29638.png]Click to view image
Camper Interior donor:
[/URL]/www.vw-mplate.com/mcode.php?lang=EN&id=721 (M-Code for interior).

[kreemoweet]

[NOVA Bus]

Yes but I'm strictly speaking of the OE (1972+) ATE, which does not have a washer, and for that WW booster, it did have have some adjustability, it still does not compare to original. You must have access to machine shop equipment, that's great, fab your own parts!!👍
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********************************
1977 Transporter / Weekender
- GE engine, L-Jetronic w/ hyd. lifters
- Brown Beige plaid P27 Interior (ED)
http:/[url=http://www.vw-mplate.com/mplate-29638.png]Click to view image
Camper Interior donor:
[/URL]/www.vw-mplate.com/mcode.php?lang=EN&id=721 (M-Code for interior).