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 Page 1 of 2 12
Username Post: Self adjusting brakes        (Topic#351527)
omarine 
Contributor
Posts: 149

Loc: San Diego
Reg: 06-29-15
06-11-18 07:53 PM - Post#2736658    

So i went ahead and installed the stock type self adjusting brake hardware that was introduced in 63 on my 61. The front brakes seem to stay adjusted with a slight rub when rotating the wheels.

The rears seem to really wear and they dont slef adjust like th front does.

Kind of puzzling, the star wheel could use a bunch of adjusting after about a week of driving.

I am using a proportioning valve because after installing a dual master, i noticed the rears were working too hard. Did t really solve the issue.

Thanks for any insight. I really like manual drums but adjusting star wheels weekly gets old.

Cheers
Oscar

61 Impala bubbletop, 283, 2bbl Rochester, generator, points and drum brakes- daily driver
'49 Harley Davidson FL - Panhead


 
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japete92 
"4th Year" Silver Supporting Member
Posts: 967
japete92
Loc: No. Virginia
Reg: 01-18-13
06-12-18 06:40 AM - Post#2736691    
    In response to omarine

  • omarine Said:
So i went ahead and installed the stock type self adjusting brake hardware that was introduced in 63 on my 61. The front brakes seem to stay adjusted with a slight rub when rotating the wheels.

The rears seem to really wear and they dont slef adjust like th front does.

Kind of puzzling, the star wheel could use a bunch of adjusting after about a week of driving.

I am using a proportioning valve because after installing a dual master, i noticed the rears were working too hard. Did t really solve the issue.

Thanks for any insight. I really like manual drums but adjusting star wheels weekly gets old.

Cheers
Oscar



A proportioning valve serves no purpose on those drum brakes. The front bias brake distribution is obtained via different size brakes (front from rear). The concept requires equal hydraulic pressure front and rear. A proportioning valve would have to be set to equalize the pressure for the system to work as designed. Why bother?

Also, do you perhaps have the front brakes on the rear? and vice versa? The wider drum/shoes go on the front.

And, if the master cylinder does not have a internal pressure regulating valves (many do not because they are used for disc brakes), external ones need to be added, one on each branch.

Pete



Edited by japete92 on 06-12-18 06:46 AM. Reason for edit: No reason given.

 
Verne_Frantz 
61-64 Subject Matter Expert
Posts: 5348
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
06-12-18 06:53 AM - Post#2736694    
    In response to omarine

When changing a pre-'63 system to self adjusting, you also have to change the star wheel adjuster. The original backing plates will also have the open slot for manual adjustment in the wrong place for the new brakes. Make sure that when the adjuster lever travels downward, that it turns the star wheel to expand the adjuster, rather than retract it.

Verne



 
DZAUTO 
Senior Member
Posts: 8486

Loc: Mustang, OK, USA
Reg: 12-25-99
06-12-18 10:20 AM - Post#2736713    
    In response to Verne_Frantz

  • Verne_Frantz Said:
When changing a pre-'63 system to self adjusting, you also have to change the star wheel adjuster. The original backing plates will also have the open slot for manual adjustment in the wrong place for the new brakes. Make sure that when the adjuster lever travels downward, that it turns the star wheel to expand the adjuster, rather than retract it.

Verne



Yep, on original (62-older) non-self adjustable brakes, all 4 of the star adjusting wheels are ALLLLLLLLLLLLL right hand threaded. But on self adjusting star wheels, THEY ARE LEFT AND RIGHT HAND THREADED--------------ARE YOU SURE YOU HAVE THE ADJUSTING WHEELS ON THE CORRECT SIDES???



 
Brian64SS 
Frequent Contributor
Posts: 1160
Brian64SS
Loc: Milwaukee, Wi
Reg: 09-30-00
06-12-18 11:11 AM - Post#2736717    
    In response to DZAUTO

Along with wider shoes, the front brakes use larger bore wheel cylinders so more volume of fluid has to go to the fronts than to the rears to get the same travel. Eliminate the proportioning valve and make sure your front brakes are connected to the larger port on your dual master cylinder. I don't recall for sure which one but I think it's the rear one. Sending more fluid to the rears could be the problem.

I turn the passenger side Tee around and move it to the driver's side. Pipe the larger MC port into the large Tee port (now facing back) then to the front wheels from there. I save the old driver's side Tee and the pipe that went across the cross-member in case I want to switch it back someday.

Brian
1964 Impala SS, 283 (not original), 4-speed (25 years)
1964 Impala 4-door hardtop, 283 Powerglide (2 years)
They made a million but I only have two.


 
omarine 
Contributor
Posts: 149

Loc: San Diego
Reg: 06-29-15
06-12-18 11:27 AM - Post#2736718    
    In response to Brian64SS

THanks for all the replies. To calrify:

1. YES, front drums and rear drums are where they should be,

2. I replaced single MC with two port MC, when I did, the rears locked up easily, so I put the proportioning valve on to mitigate that.

(larger port plumbed to front junction blocks with same 1/4" line as factory. Rear gets 3/16" line all the way to the back...)

3. All hardware is on the correct sides regarding star wheel threads. And adjusters sit centerline to the star wheels. By hand, they all do what's expected.

The fronts keep good adjustment. The rears are new Raybestos kits. They adjust, but the don't keep them tight as desired. The pedal travels far, and when I turn the star wheel by hand, I get good pedal action....

It just wont do it on its own-- rear only...



61 Impala bubbletop, 283, 2bbl Rochester, generator, points and drum brakes- daily driver
'49 Harley Davidson FL - Panhead


 
turbo38s10 
"7th Year" Gold Supporting Member
Posts: 1541
turbo38s10
Loc: Agawam,MA
Reg: 09-17-09
06-12-18 11:51 AM - Post#2736720    
    In response to omarine

Can you post a picture of the rears. Sounds like the springs are not doing their job. Is the lever moving correctly?



 
omarine 
Contributor
Posts: 149

Loc: San Diego
Reg: 06-29-15
06-12-18 12:02 PM - Post#2736721    
    In response to turbo38s10

YES, I can pics after work. I think I used all new hardware about 3 mos ago. Definitely had spring tension, used the tool and it was tight.

61 Impala bubbletop, 283, 2bbl Rochester, generator, points and drum brakes- daily driver
'49 Harley Davidson FL - Panhead


 
55Brodie 
Contributor
Posts: 151
55Brodie
Age: 66
Loc: Little River, SC
Reg: 12-26-15
06-12-18 12:30 PM - Post#2736726    
    In response to omarine

Have the rear drms been machined beyond their maximum diameter? Are the primry shoes in their correct location?



 
japete92 
"4th Year" Silver Supporting Member
Posts: 967
japete92
Loc: No. Virginia
Reg: 01-18-13
06-12-18 12:35 PM - Post#2736727    
    In response to omarine

The 'self adjusting' only works by pumping the brake pedal with the car moving backwards. You likely already know that but I mention it just in case you do not.

Just trying to be helpful. No disrespect intended.

Pete



 
omarine 
Contributor
Posts: 149

Loc: San Diego
Reg: 06-29-15
06-12-18 02:41 PM - Post#2736739    
    In response to japete92

yes, the primaries are facing rear as they should and I also pump the hell out of the brakes in reverse.

I know I was coming up to the service limit on the drum when I turned it, but it wasn't over.

I'd still think that the adjusters wouldn't know which is worn, the shoes or the drums, and it would adjust until the pedal was firm again. or am I making assumptions?

thanks again



61 Impala bubbletop, 283, 2bbl Rochester, generator, points and drum brakes- daily driver
'49 Harley Davidson FL - Panhead


 
junky 
Valued Contributor
Posts: 2507

Loc: Northeast CT
Reg: 06-27-10
06-12-18 04:54 PM - Post#2736752    
    In response to omarine

  • omarine Said:
yes, the primaries are facing rear as they should and I also pump the hell out of the brakes in reverse.





You have the shoes on backwards!

Primary (shorter lining) should be facing forward, and the longer lining should be facing rearward. One problem that I have recently learned about, is that some of the shoes that are being sold today, both primary and secondary shoes have the same length linings. If this is a problem with your shoes, you can easily remedy it by cutting off the excess lining material, and chamfering (tapering) the edge of the brake shoe lining material.

Never argue with an idiot. He'll drag you down to his level, then beat you with experience.


 
turbo38s10 
"7th Year" Gold Supporting Member
Posts: 1541
turbo38s10
Loc: Agawam,MA
Reg: 09-17-09
06-13-18 05:15 AM - Post#2736808    
    In response to junky

This is correct see page 6-5.
https://www.dropbox.com/sh/e6y4bdp4z7oagvr/AA DzV7r...



 
YOUNG57 
Frequent Contributor
Posts: 1041

Loc: Tennessee
Reg: 12-06-10
06-13-18 07:48 AM - Post#2736817    
    In response to omarine

Normally brakes do not wear fast enough to need manual or self-adjusting every two or three weeks of daily driving. Sounds like your self-adjusters are un-adjusting your brakes.

Is the dual master cylinder you installed for drum / drum brakes or for disc / drum brakes. Disc / drum master cylinders have an internal proportion valve that gives the rear brakes a different bias.

Drum / drum dual master cylinders do not use internal or external proportioning valves. Drum / drum brakes rely on the larger front and smaller rear wheel cylinders and shoes to proportion the braking bias.






 
omarine 
Contributor
Posts: 149

Loc: San Diego
Reg: 06-29-15
06-13-18 08:20 AM - Post#2736822    
    In response to YOUNG57

thanks again for all the advice....

and I misspoke - because I always get that backwards: The LARGE shoes are facing rear. (need to keep primary and secondary straight in my head.)

It's my daily driver (60 mi a day) so two weeks is all it's taken to wear the shoes EVEN before I installed the adjusters.

The star wheels are turned down to spread the shoes - so I know that's right.

The dual master is DRUM/DRUM for 67-70 Impalas and I only added proportioning valve to the rear line only because it was locking up prematurely.

It's like it will adjust -- but BASELINE on the rear shoes is still too loose and it doesn't continue to adjust from there- and that's where the pedal travels too far for my liking...





61 Impala bubbletop, 283, 2bbl Rochester, generator, points and drum brakes- daily driver
'49 Harley Davidson FL - Panhead


 
japete92 
"4th Year" Silver Supporting Member
Posts: 967
japete92
Loc: No. Virginia
Reg: 01-18-13
06-13-18 08:54 AM - Post#2736827    
    In response to omarine

  • omarine Said:
thanks again for all the advice....

and I misspoke - because I always get that backwards: The LARGE shoes are facing rear. (need to keep primary and secondary straight in my head.)

It's my daily driver (60 mi a day) so two weeks is all it's taken to wear the shoes EVEN before I installed the adjusters.

The star wheels are turned down to spread the shoes - so I know that's right.

The dual master is DRUM/DRUM for 67-70 Impalas and I only added proportioning valve to the rear line only because it was locking up prematurely.

It's like it will adjust -- but BASELINE on the rear shoes is still too loose and it doesn't continue to adjust from there- and that's where the pedal travels too far for my liking...








"... I only added proportioning valve to the rear line only because it was locking up prematurely."

I do not believe you have addressed the real problem causing the rear brakes to lock up prematurely. The addition of a proportioning valve is a band aid covering some other problem. Is that causing your 'adjustment' problem? Don't know. But getting rid of the proportioning valve and finding/fixing the real problem is where I would start.

Also, just because an after market vendor says his master cylinder is for drum brakes, does not mean it has the internal residual pressure regulator feature. It simply means that if one adds the proper components (external residual pressure regulators?), the master cylinder will do its job. Again. is that causing your problem? Don't know. But I would look into it.

Just trying to be helpful.

Pete



Edited by japete92 on 06-13-18 09:44 AM. Reason for edit: No reason given.

 
omarine 
Contributor
Posts: 149

Loc: San Diego
Reg: 06-29-15
06-13-18 11:08 AM - Post#2736837    
    In response to japete92

the rear brakes not adjusting all the way when driving in reverse and braking existed way before I added the prop valve.

My logic was that if the rears are working harder than they should, my rear shoes are wearing faster than the adjusters can keep them adjusted.

Well, even with the prop valve, the adjustment in the rear brakes is the same: Full automatic adjustment doesn't make the pedal as firm as when I manually turn the star wheels...that's what's puzzling considering the fronts adjust fine...

61 Impala bubbletop, 283, 2bbl Rochester, generator, points and drum brakes- daily driver
'49 Harley Davidson FL - Panhead


 
turbo38s10 
"7th Year" Gold Supporting Member
Posts: 1541
turbo38s10
Loc: Agawam,MA
Reg: 09-17-09
06-13-18 01:20 PM - Post#2736844    
    In response to omarine

it's starting to sound like bad hardware. I would get a new set of adjusting springs or a rod is wrong. I'm leaning toward the adjuster arm is not traveling far enough to the next click on the star wheel. See if someone here has a set of rear original used hardware. You never know what your getting with the new stuff.

Question is are your shoes actually wearing or arew the adjusters backing off.



Edited by turbo38s10 on 06-13-18 01:26 PM. Reason for edit: No reason given.

 
55Brodie 
Contributor
Posts: 151
55Brodie
Age: 66
Loc: Little River, SC
Reg: 12-26-15
06-13-18 02:12 PM - Post#2736852    
    In response to omarine

My money is on the drums having reached their service limit.



 
omarine 
Contributor
Posts: 149

Loc: San Diego
Reg: 06-29-15
06-13-18 02:16 PM - Post#2736853    
    In response to turbo38s10

thanks Turbo,

When done by hand, the adjuster does what's expected.

Then it hit me...is it normal for the pedal to travel about 1/2 to floor with brake adjusters?

That's roughly even with the gas pedal. Maybe it's working as it should.

It just leaves me wanting more tension. When I manually adjusted the star wheels, I got the pedal height I wanted, but it only would last about 2 weeks, which is what started this whole thread.

I can even feel it in the parking brake pedal.

might just knotch the drums for star wheel access and just accept the fact that I have to jack up the rear wheels every two weeks just as I have for the last few years since restoring the car....

61 Impala bubbletop, 283, 2bbl Rochester, generator, points and drum brakes- daily driver
'49 Harley Davidson FL - Panhead


 
japete92 
"4th Year" Silver Supporting Member
Posts: 967
japete92
Loc: No. Virginia
Reg: 01-18-13
06-13-18 02:48 PM - Post#2736856    
    In response to omarine

  • omarine Said:
the rear brakes not adjusting all the way when driving in reverse and braking existed way before I added the prop valve.

Did your rear brakes grab before changing master cylinders? If not, you have something wrong that goes back to that.

IF (a very BIG 'IF") your master cylinder does not have residual pressure valves, you MAY be leaking air into the system thru the wheel cylinder seals. That MAY cause your soft pedal that you are attributing to 'poor adjustment'.


My logic was that if the rears are working harder than they should, my rear shoes are wearing faster than the adjusters can keep them adjusted.

Your logic is incorrect. These GM's drum brake systems are based on, and function properly with constant hydraulic pressure in the entire system.

I can't trouble shoot your brakes over the net. I am simply noting some things you do (proportioning valve) have wrong, and some things that may (residual pressure valve) have wrong. My suggestions are more 'process' oriented. Give them whatever weight you deem appropriate.


Well, even with the prop valve, the adjustment in the rear brakes is the same: Full automatic adjustment doesn't make the pedal as firm as when I manually turn the star wheels...that's what's puzzling considering the fronts adjust fine...





 
omarine 
Contributor
Posts: 149

Loc: San Diego
Reg: 06-29-15
06-13-18 03:07 PM - Post#2736859    
    In response to japete92

Pete- really appreciate the insight - I wasn't thinking about the MC, although, yes, the rears were locking too easily until I put the prop valve in. the MC came from booster dewey and I told him what I was using it on, so I am assuming it's appropriate for my setup.

I guess the bottom line in all of this is, when the adjusters were manual star wheels, my braking action AND pedal travel was excellent (about 3-4" pedal travel, now its more like 6-7" of pedal travel).

Once I put the adjusters on, and use them as intended, the rears just don't stay adjusted like the fronts.

I may just go back to manual star wheels or use access hole for manual adjusting for that reason ...

61 Impala bubbletop, 283, 2bbl Rochester, generator, points and drum brakes- daily driver
'49 Harley Davidson FL - Panhead


 
japete92 
"4th Year" Silver Supporting Member
Posts: 967
japete92
Loc: No. Virginia
Reg: 01-18-13
06-13-18 03:23 PM - Post#2736862    
    In response to omarine

Hope you sort everything out to your satisfaction.

Here's some info you may find helpful:

https://www.mico.com/sites/default/files/d ocument-...

https://www.youtube.com/watch?v=6B8a6enp1bg

Pete



 
turbo38s10 
"7th Year" Gold Supporting Member
Posts: 1541
turbo38s10
Loc: Agawam,MA
Reg: 09-17-09
06-13-18 04:40 PM - Post#2736869    
    In response to japete92

It still sounds like the star wheels are backing off to me. Are the levers staying engaged with the star wheels or are the pulling away at rest?



 
Verne_Frantz 
61-64 Subject Matter Expert
Posts: 5348
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
06-13-18 07:34 PM - Post#2736897    
    In response to turbo38s10

I know this seems to be covering the same ground again, but if your rear brakes and pedal travel are changing within two weeks of driving, I would suggest that you double check the star wheel adjusters on the rear and make certain they are expanding when the wheel is pulled down by the adjusted.

If that's not it, you may need to change the front hoses.

Verne



 
junky 
Valued Contributor
Posts: 2507

Loc: Northeast CT
Reg: 06-27-10
06-13-18 08:11 PM - Post#2736902    
    In response to turbo38s10

  • turbo38s10 Said:


In figure 7 the primary shoe is in front, and in figure 8, it is in the rear. All that this shows is that the people that were writing the manuals were not mechanics, but technical writers that never put their hands on a SAE wrench!

Never argue with an idiot. He'll drag you down to his level, then beat you with experience.


 
junky 
Valued Contributor
Posts: 2507

Loc: Northeast CT
Reg: 06-27-10
06-13-18 08:25 PM - Post#2736907    
    In response to omarine

I am hesitant to wade into this debacle, because I am a firm believer that if you know very little about brakes, that you are putting yours and other lives at risk, when you do your own repairs. With that being said, I am going to try to help you with this problem. First, did you replace the wheel cylinders, and the brake hose over the rear axle? I ask this, because you might have the wrong wheel cylinder, or the hose over the rear axle might be holding pressure on the cylinder, due to it being old and failing.
Next, have you backed off of the parking brake cable when you did the original installation? Next, when you assembled the shoes to the hardware, did you check for any burs or other issues? I am assuming that these are relined brake shoes. Might it be possible for you to post a close up picture of each of the rear brakes, with good lighting? Were you having problems before you changed out the single master cylinder for the dual master cylinder?
Finally, I would like you to drive on a deserted road, and apply the brakes, and note how far the pedal travel is to bring the car to a complete stop. Now, do the same thing, and depress the parking brake about 4 notches before you apply the brake, and report back what you notice. Finally, count the total number of clicks until the parking brake is fully engaged, and report this.
This question is up to you to decide. If the problem can't be resolved quickly, would you be willing to reinstall the original master cylinder, and remove the proportioning valve, and put everything back together as an experiment moving toward resolution of where the problem lies?
I would also like to see a picture of the top of the master cylinder with the cover removed, and your telling me where the forward compartment of the master cylinder is plumbed to... front or rear?

Never argue with an idiot. He'll drag you down to his level, then beat you with experience.


 
junky 
Valued Contributor
Posts: 2507

Loc: Northeast CT
Reg: 06-27-10
06-13-18 08:38 PM - Post#2736909    
    In response to junky

I just thought of one more item. You say that you got the master from Booster Dewey, did you also get the booster unit from him at the same time?
Would you back off on the two nuts that hold the master cylinder to the firewall or the booster, and let me know if the master cylinder starts to pull away from the booster or firewall, or it just stays in place.

Never argue with an idiot. He'll drag you down to his level, then beat you with experience.


 
impala 
Frequent Contributor
Posts: 1252
impala
Loc: Pittsburgh, PA USA
Reg: 07-13-00
06-14-18 06:29 AM - Post#2736932    
    In response to omarine

  • omarine Said:
I know I was coming up to the service limit on the drum when I turned it, but it wasn't over.



Have the rear shoes been contoured to match the diameter of the drums since they have been turned close to the service limit?
Could the shoes be rocking preventing the self adjusters from working properly?
impala


61 Impala Convertible, AACA Senior Grand National
99 Jaguar, XK8
11 Silverado
18 Equinox


 
55Brodie 
Contributor
Posts: 151
55Brodie
Age: 66
Loc: Little River, SC
Reg: 12-26-15
06-14-18 08:07 AM - Post#2736941    
    In response to impala

The shoes will attempt to "contour themselves" along the horizontal centerline of the axle when the drums are worn. This was my point exactly.



 
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