[pggto]

I'm helping a friend with the brakes on his 71 GTO. The car has 4 wheel manual drum brakes, I've never done front drums, plenty of rear drums. We replaced all four wheel cylinders and front brake hoses along with new shoes and brake hardware and all the drums were cut. I adjusted the rear brakes like I normally do, with the shoes lightly dragging on the shoes. I adjusted the front brakes the same way, you can free spin the drum about a turn or two and hear the shoes lightly dragging on the drum.

The brakes don't feel right. Car doesn't stop well. Do I need more front brake adjusted into the drums? I'll try that next. I saw something on the internet last night that you should adjust the fronts with the tire on and have a lot more drag than I do now. Kind of one revolution of free spin with the tire on.

Any tips for adjusting 4 wheel manual drums?

Not ruling out the master cylinder, might replace that next for piece of mind.

Thanks

[Formulas]

Did you clean and lubricate the star adjuster so it does its job easier?
if everything works like day 1 jamming on the brakes in reverse a few times should take care of a large adjustment problem

With a system that was dismantled that much another bleed a few days later helps in my experience

Also you may notice a degraded braking feel do to the arc of the new shoe vrs the drum that has been used and turned they are not exactly the same size circle so a lesser contact patch results ( they have to bed in )

[steve25]

Make sure the threads on the adjuster are clean, then coat with antiseize and run it in and fully 3 to 4 times to coat all the way down in it, then you should adjust the shoes with the drum off such that you can not get the drum on, and then back the adjustment down until you can just literally rock the drum only enough to get it back on.
The adjusters need to move with just light force otherwise they will never self adjust when doing back up moves!
I hate to ask this, but you guys do have the adjusters installed on the right size, not like I did once back when I was 16 and doing my first brake job, lol!

Oh , and what the heck is a 71 car doing with drum ft brakes?
It must have been special ordered that way no?

[pggto]

The stars adjusters have been cleaned and lubed. The backing plate pads have been cleaned an lubed as well.

[pggto]

Originally Posted by steve25

Make sure the threads on the adjuster are clean, then coat with antiseize and run it in and fully 3 to 4 times to coat all the way down in it, then you should adjust the shoes with the drum off such that you can not get the drum on, and then back the adjustment down until you can just literally rock the drum only enough to get it back on.
The adjusters need to move with just light force otherwise they will never self adjust when doing back up moves!
I hate to ask this, but you guys do have the adjusters installed on the right size, not like I did once back when I was 16 and doing my first brake job, lol!

Oh , and what the heck is a 71 car doing with drum ft brakes?
It must have been special ordered that way no?

I'm pretty sure the star wheels are correct, they move in the direction the adjuster bracket would move in the downward stroke.

The 71 GTO is a Judge with manual drums! Not sure on the special order, I will have to ask him. Lets get the big engine and the crappy brakes! What the hell were they think'n! lol

[77 TRASHCAN]

The 64 GTO could of had front disc brakes AND radial tires, but Ed Whoever, then Pres of GM, didn't want Pontiac stealing the number one spot from Chevrolet, or so I've read...

Get all the above stuff done correctly, adjust them till there's a slight drag. Get in car and push on brake pedal, firmly a couple of times, to hopefully center the shoes. Then adjust them closer for slightly more drag. Making sure both sides feel evenly adjusted. Then got for a careful test drive, to see how brakes respond.May need another adjustment....

[Schurkey]

Originally Posted by 77 TRASHCAN

adjust them till there's a slight drag. Get in car and push on brake pedal, firmly a couple of times, to hopefully center the shoes. Then adjust them closer for slightly more drag.

Yup. Actually applying the brakes allows the shoes to "align" themselves to the drums. Then adjust again. Can make a BIG difference.

I didn't see anything in your post about repacking/adjusting the front wheel bearings. If they're even slightly out-of-adjustment, you'll get a little brake "drag" when adjusting even if the adjustment is WAY out, because the drum doesn't run true to the shoes. How old is that grease?

Of course, you already know about primary and secondary shoes...

When I get to the point that I trust the brakes, I drive ~40 mph, and stop HARD until I'm going 25 or so. Repeat several times. Hard stops "bed" the pads/shoes, it's essential for proper brake lining replacement--but DON'T go all the way to zero mph, because you want the cooling air flow especially with vented rotors. Depending on the lining material, I might even make a couple of 75-to-35 mph "stops" on a low-traffic highway.

[pggto]

Originally Posted by Schurkey

Yup. Actually applying the brakes allows the shoes to "align" themselves to the drums. Then adjust again. Can make a BIG difference.

I didn't see anything in your post about repacking/adjusting the front wheel bearings. If they're even slightly out-of-adjustment, you'll get a little brake "drag" when adjusting even if the adjustment is WAY out, because the drum doesn't run true to the shoes. How old is that grease?

Of course, you already know about primary and secondary shoes...

When I get to the point that I trust the brakes, I drive ~40 mph, and stop HARD until I'm going 25 or so. Repeat several times. Hard stops "bed" the pads/shoes, it's essential for proper brake lining replacement--but DON'T go all the way to zero mph, because you want the cooling air flow especially with vented rotors. Depending on the lining material, I might even make a couple of 75-to-35 mph "stops" on a low-traffic highway.

Yes we did repack the wheel bearings. We did apply the brakes while on the jack stands to center the shoes also. I think we need to try to seat/bed the shoes. I don't think when he drove it the first time he got on the brakes very hard.

[hal101]

when you say The brakes don't feel right. Car doesn't stop well do you mean the peddle is low or it takes a lot of effort
because manual will always take more effort

[Bermuda Blue]

Contrary to what most people will say, drum brakes will send you through the windshield when you stand on the brakes if properly adjusted and maintained. Assuming you have good tires of course.

Is the pedal soft? Does it have a lot of travel?

The pedal should travel about 1" and then go rock hard. If not, bleed and adjust again.

A drum system should "self bleed". If you open the bleeders and remove the MC cover the fluid should drain on its own. If not you have distribution block, MC, SC or line issue.

Also keep in mind that the front brakes will not build pressure until the rears build pressure first. So if your rears are way out you will have a lot of pedal travel and poor braking action.

[mgarblik]

Assuming you have everything assembled correctly, all 4 primary shoes, the short ones facing forward and so forth. If they still feel lousy, I would highly recommend having the shoes arced to fit the now larger, machined drums. It's possible only 30-40% of the friction material is actually contacting the drums if they are machined to the limit or beyond. Properly arced shoes make a huge difference, especially on a manual drum 4-wheel set-up. Good luck

[steve25]

Also if the 4 shoe support points on the backing plate where never greased up during the life of the car then they can be badly worn and not allow the shoes to expand out like they should!

[george kujanski]

If the mechanical stuff is correct, install with a slight drag, then use the brakes in reverse several times so they self adjust correctly.

George

[pggto]

Originally Posted by steve25

Also if the 4 shoe support points on the backing plate where never greased up during the life of the car then they can be badly worn and not allow the shoes to expand out like they should!

I cleaned and put a little lube on the backing plate pads. They were in very good condition, no grooves, rust or worn spots.

[pggto]

Hopefully I will get a chance to see what the brakes feel like in the next few days, and go from there.

Where you someone go to get the brake shoes re arched? I understand the concept, but have never had it done, nor do i know any place that is capable of doing it.



Thanks for the replies.

[SRR]

Give it a few stops to bed in like mentioned, they will get better with time. My 70 Skylark has 4 wheel man. drums. They will never be "great" but will stop the car. Eventually...

[Old Goat 67]

Maybe.

[steve25]

New pads and shoes need to bed in and its heat that gets this done!
The pads and or shoe lining transfers over a coating the increases gripping power.
3 or 4 very hard stops from 60 mph should do it.

Just note a very important fact which is you do not want the rear brakes to lock up before the fronts do, other wise your headed loosing control and for a spin out be it to the left or the right dependent on the traction of each rear tire!!

[TedRamAirII]

Re=Arcing brake shoes has not been done for a long time. The issue of grinding asbestos linings into dust was forbidden. One thing you can do is use a press to slightly flatten the arc of the shoe to match the drum. I did see a guy take sand paper for a straight line air sander and stick it to the inside of a drum, and slide the shoes until they had full contact, pretty slick. You could even bolt the drum to the axle flange, drum facing out, and put the car in gear and hold the shoes against the drum for Power Brake Arcing.

[TCSGTO]

Grinding linings to fit drums will just make them perform slightly better right after installation. The shoes themselves distort a fair amount under braking load so it’s kind of like honing a cylinder without a torque plate. As was stated they will bed in and conform to the drum with some use.