Adjusting Self-Adjusting Brakes

[Jay Laifman]

FWIW, I came up with a plan of sorts to provide a different spring to help improve the self adjusting brakes. This is just a rough idea. Here is video of how it works and shows what NEEDS to happen to make it work - the lever needs to go back and down. The Alpine has the spring which stops working after a while. The MGC and the TR GT6 MkIII have nothing. So super bad for them.

Rough picture. But it's to help explain. The sketch on the left is a red line and green line and circle. The red line is a bolt through the adjusting arm. The green line is an attached rod or cable going away from your view and through the backing plate - the green circle is the hole through the backing plate.

The sketch on the right is the side view. The red and green are the same parts. The black line is the backing plate. The yellow squiggle is a spring.

so when the parking brake lever is pulled up, as normal, it pulls the end of the adjusting arm which pushes the other end up (the end that shows in the picture). This then pulls the green rod or cable up, compressing the spring. Then when the parking brake is released, the spring I have pulls the arm back down.

And if it is positioned right, it will make sure the arm comes in enough to catch the next star.

 

[DanR]

Just saw this : Self adjuster for drum brakes (Samostav) - YouTube

 

[Shannon Boal]

}"I still have faith I will get this to work right!"{
It can be done! I did it, and my self-adjusters work fine. HOWEVER, it took heroic measures (aligning and bending hardened steel levers, precision welding the one that I snapped, boring out or shimming up the adjuster recess in the wheel cylinder, stoning the parts let the cylinder slide, filing all the teeth on the star-wheel, squaring the hardened steel edge of the lever, straightening the brackets that hold the lever springs, grinding away part of the brake shoes that fouled the lever).... I did all of that stuff, (maybe to prove that I could).....BUT, in terms performance and time spent, I consider Dan R.'s disc brake conversion to be better. At the end of the day, I have a perfect set of drum brakes: for which no new drums are available.

 

[Shannon Boal]

Fantastic video! Outstanding job documenting this....... I see that the adjuster does not fit in it's bore properly, and when it wobbles, the lever skips. Mine was the same. This was not the finest hour for British workmanship!

 

[Bill Blue]

Fantastic video! Outstanding job documenting this....... I see that the adjuster does not fit in it's bore properly, and when it wobbles, the lever skips. Mine was the same. This was not the finest hour for British workmanship!

I disagree. You are unfairly bashing workmanship. I place the blame squarely on poor design. Workmanship can go only so far, as you demonstrated. There is only one place to blame for poor design, upper management.

Bill

 

[Jay Laifman]

I disagree. You are unfairly bashing workmanship. I place the blame squarely on poor design. Workmanship can go only so far, as you demonstrated. There is only one place to blame for poor design, upper management.

Bill

I just want to be clear what "upper management" you are talking about here. Sunbeam was the ones who improved the design. None of the other companies that I've seen have the return spring that actually gives it a chance for working. So all the more reason to spend the time and try to make it work right.

And kudos to the original attempt too. They were improving the long successful drum brakes. The more modern drum brakes with self adjusting features are not all that different.

 

[DanR]

Jay, It could be the Chrysler Corp Management Bill is referring to. I think they really screwed the Rootes Company even before taking over totally.

 

[husky drvr]

Considering this unit was Girling's design and supplied to Rootes as a subcontractor parts system, it would still be difficult to blame Rootes for being sold a "pig in a poke". Don't forget Rootes fairly quickly, in manufacturing terms, changed back to the manual adjusters.

 

[Jay Laifman]

I suspect the only thing that Rootes/Chrysler did here is choose to approve the self adjusting feature - which could have appeared to be forward thinking and an improvement. And perhaps not going with discs yet. They didn’t design self adjusting. And as mentioned, if anything, they also agreed to the expense of the added spring that no one else had.

 

[DanR]

Good points!

 

[Gordon Holsinger]

FWIW, I came up with a plan of sorts to provide a different spring to help improve the self adjusting brakes. This is just a rough idea. Here is video of how it works and shows what NEEDS to happen to make it work - the lever needs to go back and down. The Alpine has the spring which stops working after a while. The MGC and the TR GT6 MkIII have nothing. So super bad for them.

Rough picture. But it's to help explain. The sketch on the left is a red line and green line and circle. The red line is a bolt through the adjusting arm. The green line is an attached rod or cable going away from your view and through the backing plate - the green circle is the hole through the backing plate.

The sketch on the right is the side view. The red and green are the same parts. The black line is the backing plate. The yellow squiggle is a spring.

so when the parking brake lever is pulled up, as normal, it pulls the end of the adjusting arm which pushes the other end up (the end that shows in the picture). This then pulls the green rod or cable up, compressing the spring. Then when the parking brake is released, the spring I have pulls the arm back down.

And if it is positioned right, it will make sure the arm comes in enough to catch the next star.
View attachment 24425

 

[Gordon Holsinger]

I rebuilt the self adjusting brakes on my SV I found replacement adjusters from a guy called Guestie’s garage, I found the retractor springs at SS new w/c VB Brake shoes VB. They are a pain but must be maintained, and set up properly. Girdling self adjusting we’re used on MGC, some Triumph GT 6, and some alpines!

 

[Jay Laifman]

Yeah, I have a pair of retractor springs on the way from SS.

As I think about it, I realize that the retractor springs I have are stretched such that when it's all at rest, there is a gap between the spring and the lever it is supposed to be pushing on. If there was a way to tighten the spring or make it adjustable, that might also solve this part of the problem.

My idea above is essentially an adjustable spring. We'll see how tight it is with the new spring from Rick. If it starts off too lose, I might drill a hole in the little bracket that mounts the spring so that I can tighten it by mounting it a bit more twisted.

 

[Jay Laifman]

Interesting description of the 1963 GM self adjusting drum brakes. Note the pretty hardy, and well placed return spring.

Note too the description about how braking while in reverse actuates it. I've seen people say that about the Alpine system. I'm not sure that I see how ours does that. I believe ours works primarily or even solely with the hand brake pull.

 

[puff4]

The brake adjuster should, as shown in the video, flick the adjusting wheel every time you pull the handbrake, slowly advancing the wheel and tightening the brakes until the brakes are tight enough that pulling the handbrake will no longer pull far enough to index the adjuster wheel because the brakes only take just a bit of a pull to engage the handbrake. The important part is that the handbrake cable *must* retract fully each time, or else the adjusting finger won't properly advance the wheel. As such, the handed springs on the outside of the brake mounting plates - the thick, coiled one that pulls out on each wheel cylinder's handbrake lever - must be in good condition and properly mounted to ensure that lever fully retracts. The mounting stub for this spring, and the bracket that holds it, must not be bent or damaged. Also, the cable must be kept lubricated so that it will retract and not inhibit movement of the arms. Further, there is a rubber grommet on the handbrake crossbar, located on the bracket behind the rear axle pumpkin, that must be in place and lightly lubricated to ensure the crossbar moves easily. If all this is in good order, the self adjusting brakes work fine (at least mine do).

 

[Shannon Boal]

"I disagree. You are unfairly bashing workmanship."
Fair point, Bill.
Quality control choices come from the top. Well, the excessive variance in fit would be a quality control issue. The blame often does fall on, the people thrown under the bus often are: workmen; hence "not their finest day". Another example is my dad's late series V Alpine, which always had a buzzing noise in the carb linkage. I found one con rod eight grams heavier than the other three (two grams would be fine), and having balanced that, the buzzing noise was gone. That would be an example of management, too.... maybe choosing production goals over quality controls.

 

[Shannon Boal]

Kevin, that is the best description of the self-adjusting action I have seen anywhere.
Regarding the backing plate, "The mounting stub for this spring, and the bracket that holds it, must not be bent or damaged." I think that my "stubs", which were bent, allowed the springs to fall off. Maybe that is why they were missing.
I am very happy SunbeamSpecialties had new springs. I straightened
my "stub" brackets to be ninety degrees from the backing plate

 

[Bill Blue]

"I disagree. You are unfairly bashing workmanship."
Fair point, Bill.
Quality control choices come from the top. Well, the excessive variance in fit would be a quality control issue. The blame often does fall on, the people thrown under the bus often are: workmen; hence "not their finest day". Another example is my dad's late series V Alpine, which always had a buzzing noise in the carb linkage. I found one con rod eight grams heavier than the other three (two grams would be fine), and having balanced that, the buzzing noise was gone. That would be an example of management, too.... maybe choosing production goals over quality controls.

I became very aware of the "workmanship" issue when I bought Gremlin way back when. While as a new car purchaser, I was admiring the dash, I noticed horrible gaps between the dash and the molded plastic it fit into. Thinking it was just horrible workmanship on the part of the assembly guy, I decided I would rework the installation. After surveying the problem for an additional minute, I concluded the assembler had done an amazing job of installing a dash piece that did not fit the opening. I don't know who okayed the production of a misfitting part, but it certainly wasn't the guy that fastened it onto the dash panel. I can only hope it was the management guy who had been sentenced to installing the crap he had okayed the production of.

Bill

 

[Gordon Holsinger]

Yeah, I have a pair of retractor springs on the way from SS.

As I think about it, I realize that the retractor springs I have are stretched such that when it's all at rest, there is a gap between the spring and the lever it is supposed to be pushing on. If there was a way to tighten the spring or make it adjustable, that might also solve this part of the problem.

My idea above is essentially an adjustable spring. We'll see how tight it is with the new spring from Rick. If it starts off too lose, I might drill a hole in the little bracket that mounts the spring so that I can tighten it by mounting it a bit more twisted.

 

[Gordon Holsinger]

The retractor springs are quite stiff! Make sure your handbrake cable moves freely I took mine off and hung it up and let it soak in penetrating oil and then cleaned it out with solvent blew it out with air and then motor oil! Slides freely!