Re: 11 inch Manual Drum Brake Problems......
[Re: 70mopes]
#1631274
06/10/14 01:42 AM
06/10/14 01:42 AM
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Joined: Jan 2007
Posts: 7,664 IN
ahy
master
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master
Joined: Jan 2007
Posts: 7,664
IN
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Quote:
Thanks fellas... good info
Are you referring to the prop valve or the master cylinder holding a bit of residual pressure?
The brake hoses, lines, wheel cylinders are all new. The prop valve is the original piece off the car. I have a spare that came off a 318 manual drum brake car that I am tempted to try. It looks exactly the same and I assume that it is at this point. The master cylinder is an OEM type that I rebuilt. All seemed fine with it however I did notice that the flow of fluid coming out of the rear wheel cylinders seemed slow during the bleed process.
It is strange. I think it is set off when I get on the brake pedal hard. In both instances it seems that could have been the case. Does that raise any questions? Like I said once I got it home and on jacks I would remove the drums and have to back off the adjustors... once having done that and running some checks, everything seemed to operate as one would expect.
If it does it tomorrow, I will immediately open the wheel cylinder bleeds to see if there is residual pressure.... good idea.
With the OE setup, I believe the master was set up to hold some residual pressure. It served two functions 1) keep a little pressure on the cylinders to prevent leaks (not necessary with newer cylinders) 2) reduce lag on applying brakes. Some say the 2'nd - reduce lag - is not really needed so the residual pressure function may be "optional" with newer wheel cylinders.
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Re: 11 inch Manual Drum Brake Problems......
[Re: RapidRobert]
#1631277
06/10/14 04:57 PM
06/10/14 04:57 PM
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Joined: Jan 2003
Posts: 25,967 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,967
Rio Linda, CA
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I'm not sure I can picture a scenario where "wrong side" adjusters would tighten the brakes; in normal operation the self-adjusters only work when the brakes are applied while backing up, on forward application there is no action from the self-adjusters.
The INTERNET, the MISinformation superhighway
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Re: 11 inch Manual Drum Brake Problems......
[Re: John_Kunkel]
#1631278
06/10/14 10:45 PM
06/10/14 10:45 PM
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Joined: Feb 2003
Posts: 1,228 Maple Valley, WA
70mopes
OP
pro stock
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OP
pro stock
Joined: Feb 2003
Posts: 1,228
Maple Valley, WA
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Man.. this issue is more of a PITA than the tranny.. at least with it I saw what the problem was right away and fixed it.
Today I worked on the brakes again with less than worthy results. I made sure the adjustors were correct - which they are. I went ahead and put the drums on and then bolted the drums down without the wheels. It went from good rotation to binding with the lugs tightened. I hand sanded the whole inner ridge to smooth out that area since it appeared from the wear marks on the shoes, that area was suspect. It got better, I set the adjustors for optimum rotational feel and put the wheels back on.
I took it out for a test hop and they began to get tight again. When I came back I put it up and checked the bleeds on the wheel cylinders.. no pressure there. Drums were not bound up but they were tight. I removed the drums and everything was seated and as it should be - the shoes that is.... confounding.
When I rotated the RH wheel, 180 degrees of rotation was as expected and the other half tight.... similar but less so on the LH side.
With that I thought I may have potentially out of round drums so I took them to my local guys and then cleaned them up. Not much to clean, RH side was a bit more non concentric. When I got them home, I put them on and they rotated and sounded perfect... just as you would expect. I thought I was golden. Adusted shoes, took it out and wouldn't you know it, they got tight AGAIN!
This is getting old. I put it up on jacks and put it in gear and watched the wheels spin to see if there was any wobble or any other visual that might indicate something is amiss. I hit the brakes a bunch of times, engaged and disengaged the e-brake and it essentially ends up with the scenario where half the rotation is bound and half is not.
I ran out of time tonight so I am wondering about the next plan. I have manual adjust hardware that I was going to substitute and see how that goes. I also was going to put it up and take the wheels and drums off and rotate the axles with the engine running and trans engaged to see if there is any kind of strangeness there. It almost seems as thought the axle could be tweaked....
That's the latest.
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Re: 11 inch Manual Drum Brake Problems......
[Re: 70mopes]
#1631279
06/10/14 11:03 PM
06/10/14 11:03 PM
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Joined: Jun 2012
Posts: 1,386 Philadelphia PA
Pynzo
Drugs are bad
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Drugs are bad
Joined: Jun 2012
Posts: 1,386
Philadelphia PA
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I put in a new Raybestos brand set of adjusters front and rear on my 11" drums. New spring kit also. Just as the top springs were freshly painted, and when stretched into position, the override springs of the adjuster cables also had to be overstretched to get the paint to pop so the adjuster lever would line up correctly with the star wheel. The top lip should contact below the centerline of the star. Pull the cable and the lever should rotate the star wheel upwards one click at a time. If your adjusters are on the correct side for their thread the rod will lengthen. This action will only occur while reversing when setup properly and will not overtighten. That's what the override spring is there for. Post a pic with the drum off. Also I had to reuse the adjuster thrust washers as the new kit did not have them. They go on the free spinning side of the shaft, and never seize is better to lube the threads and free spinning side. Hope this helps.
Last edited by Pynzo; 06/10/14 11:06 PM.
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Re: 11 inch Manual Drum Brake Problems......
[Re: 70mopes]
#1631282
06/10/14 11:30 PM
06/10/14 11:30 PM
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Joined: Jan 2003
Posts: 1,286 IN
GTX4spd
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,286
IN
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Similar experience I had a few years ago involved the placement of the brake lining on the shoes. Fronts kept binding, couldn't understand why until I compared the new shoes to the originals. Went back to NAPA & went through gobs of boxes until we found shoes that the linings were same as the originals. Not clear on whether you replaced your shoes, but even if you didn't could you have switched sides? just my
"Gentlemen, we must all hang together, or surely, we shall all hang seperately."--Benjamin Franklin
www.wwnboa.org if you're interested in '62-'74 B-Bodies
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Re: 11 inch Manual Drum Brake Problems......
[Re: GTX4spd]
#1631283
06/11/14 02:10 AM
06/11/14 02:10 AM
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Joined: Jun 2004
Posts: 3,319 Chicago Burbs
sthemi
master
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master
Joined: Jun 2004
Posts: 3,319
Chicago Burbs
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To eliminate the self adjuster simply remove the cable and give it a try.. Then look at other possibilies... Another very likely cause the the parking brake hanging up, when fully assembled the shoes must both touch the center anchor pin.
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Re: 11 inch Manual Drum Brake Problems......UPDATE
[Re: Supercuda]
#1631286
09/11/14 05:13 PM
09/11/14 05:13 PM
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Joined: Feb 2003
Posts: 1,228 Maple Valley, WA
70mopes
OP
pro stock
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OP
pro stock
Joined: Feb 2003
Posts: 1,228
Maple Valley, WA
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Relighting this post to pass along findings.
The problem to the original brake issue and also the wump, wump noise coming off the rear end was the axle housing. It is bent. So bent that it could be seen with the naked eye. It was not easy to notice when in the car but once out it was. Somewhere between 5 and 10 degrees out would be my guess.
Last edited by 70mopes; 09/11/14 05:20 PM.
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