Brake Booster holding ON....FIXED!

[PocketThunder]

http://www.youtube.com/watch?v=AWTFlw17EOc

I have a 68 Charger, with a Bendix booster and master cylinder out of my donor 69 New Yorker.  The booster was rebuilt, and the master cylinder is new.  The push rod was changed from a C-body to the correct B-body rod.  My dogleg pivots freely by hand. My brake pedal holds and i have to pull it back up with my left foot.   I have plenty of vaccuum at the booster.   

I called Dewey and asked him what to do and he had me run a couple tests before i send it back.  One test was, with the engine off, step on the pedal a couple times and then push it to the floor and see if it comes back.  result-Negative. 

Then with the booster out of the car, hook up the booster to the engine while it is running and see if the push rod comes back on its own.  result-Positive.  but it didnt slide back in a smooth motion as you can see in the video. 

Any thoughts?

thanks

Paul
in St. Paul

[Just 6T9 CHGR]

Ahh geez.....although I cant offer you any suggestions I certainly hope this doesnt happen with my stuff

What did BD say about the tests?

[Chatt69chgr]

I am interested in this too as I also had a 69 NY booster reconfigured like you did.  I am years away from where you are with your project though.

[PocketThunder]

Talked to Dewey at lunch time and he said that it must be in the pedal and dogleg and that something is binding up.  It doesnt take very much of a bind to hold the pedal forward.  He said there are several types of doglegs and i was assured that the one i bought was specifically for a b-body, in fact i remember that it came out of a '69 Charger.  So i will put the booster back in the car and grease up the dog leg real good.  My suspicion is that the bolt that holds the dogleg to the mounting bracket on the car was too tight.  I will set it up with the nut loose on this bolt and see how freely the pedal moves back and forth.  Hopefully that was the problem. 

He also mentioned that if i have a different size master cylinder on the car that the hole that the rod goes into might be to big for the rod and maybe the rod is getting shifted side to side and being moved at an angle.  But i ordered the same m/c that came with the 69 new yorker, the same one that was mated up to the booster. 

Some guys at work mentioned to just put a spring on the pedal to pull it back but i'd rather not.  I want it working like its supposed to. 

[Shakey]

I thought the disc brakes on the '69 C-Bodies were made by Budd and not Bendix?   

Not that that helps you much in this situation Paul.

How about the spring - what type of shape is it in?

[Just 6T9 CHGR]

How are the plastic bushings in the bell crank itself?

The ones in mine were a bit crusty looking so I ordered up some new ones...

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=013&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=230035415842&rd=1,1

How about the spring - what type of shape is it in?

What spring?

[Chatt69chgr]

I had no idea those bushings were still available.  Does anyone have the Chrysler Part Number?  If so, we can all just go down to the dealer and order some instead of playing around with Frederick Dodge.  Note that they purposefully didn't put the Chrysler part number in the ebay add.  They don't want you to do that. 

I took the dogleg, bellcrank, or whatever it is called that I got out of the junkyard completely apart ostensibly to get all the rust off with my trusty drill/wire brush combination (I use a Dremel tool with appropriate brushes to get inside stuff).  But when I very carefully pulled the plastic bearings out, I found that whatever grease had been in there had dried up long ago.  And the shafts had some light corrosion on them.  Whole thing didn't swivel properly.  I cleaned up everything, painted appropriate parts of the mechanism, and reassembled using lubriplate grease and the thing looks and feels new.  Perfectly smooth operation.  I suppose you could tighten the captivated nuts down too much and cause some binding.  You might check to see if you piece needs any TLC.  Just a thought.

[Just 6T9 CHGR]

I am missing one of the steel spacer/bushings for mine (one of the 2 that go into either the booster rod hole or the bellcrank pushrod)

Hopefully I might have one on the way....if not I will use a brass bushing I made up for temp till I find one....

[Just 6T9 CHGR]

I had no idea those bushings were still available. Does anyone have the Chrysler Part Number? If so, we can all just go down to the dealer and order some instead of playing around with Frederick Dodge. Note that they purposefully didn't put the Chrysler part number in the ebay add. They don't want you to do that.

The part # is 2467770 and they are still avail at the dealer (using partsvoice.com)

For me ordering from eBay was easier.....

[PocketThunder]

Chris, i might have a spare bushing.  i had two of those bell cranks and one was for parts.  i'll go look tomorrow when its warmer outside..  brrrr

[Just 6T9 CHGR]

Thanks Paul, check your PM

[Shakey]

How are the plastic bushings in the bell crank itself?

The ones in mine were a bit crusty looking so I ordered up some new ones...

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=013&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=230035415842&rd=1,1

How about the spring - what type of shape is it in?

What spring?

There is a spring attached to the top portion of the brake pedal housing.  I thought it was attached to the brake pedal to help hold it up when the brakes are not applied.

[Just 6T9 CHGR]

I gotcha now Mike....I believe thats what its for as well

[mysil bergsprekken]

same problem that I've got still, the pedal won't return..

These are the reasons I can think of:
1. brake pedal pivot and bell crank not lubricated enough
2. bendix diaghram return spring worn out,
3. clogging in master cylinder piston cups worn
4. check valve not working properly

What should I do, where would you start, anybody have an idea on this, And I would really appreciate it

[PocketThunder]

same problem that I've got still, the pedal won't return..

These are the reasons I can think of:
1. brake pedal pivot and bell crank not lubricated enough
2. bendix diaghram return spring worn out,
3. clogging in master cylinder piston cups worn
4. check valve not working properly

What should I do, where would you start, anybody have an idea on this, And I would really appreciate it

FIXED!

The problem was that the bell crank pivot bolt was too tight.  I took out the bell crank and greased it, and put a lock nut on the bolt.  Now it works just fine, the pedal comes back and does not hang up at all. 

Paul
in St. Paul

[PocketThunder]

Here is my dogleg (bellcrank) installed in my 68 and working properly.

[PocketThunder]

Here is my "parts" bellcrank.  The white bushings are stuck and do not move freely like the ones in the car do.  These bushings are for the pivot rod that the unit pivots on.

[Just 6T9 CHGR]

Paul, any way you can measure the bushing thats in your spare one?  The length/width?

Thanks
Chris