2nd Gen Non-Engine/Transmission Hot brake drums after new shoes installed

[TBora]

Just installed new rear shoes (NAPA Premium). Got them adjusted per the manual and did about 10 drive backwards to full stop adjustments. Did a test drive and noticed that the drums and axle hub were overly hot. So I backed off each adjuster quite a bit (like 10-15 star wheel teeth). This time I did no back-up to full stop adjustments.



Can't loosen the shoes much more without losing my parking brake. Did another test drive (7 miles at 45 MPH) came to a stop and the drums while cooler than the first time still where hot enough that I could only hold my finger on them for about 2 seconds.



Question: Is this normal?

 

[B.G. Smith]

If you didn't turn the drums there is usually a little radius worn in each side of the drums and with the new shoes being square on the edges it's probably just that wearing off. Probably normal but you may need to re-adjust after a few miles after the corners wear off. bg

 

[TBora]

Yep, I did not turn the drums. I'll watch it and see what happens. A little problem is that I have a 450 mile trip planned next week and won't have many miles on it by the time I head out.



Thanks, B. G.

 

[HBarlow]

It sounds like you went from one extreme (too tight) after repeated backing brake applications to the other (too loose) after backing off 10-15 teeth. You may not have much rear brake now.

I would adjust them up snug again with the brake spoon and take a test drive and brake a few times. If the drums don't get hot try backing and braking once or twice then test drive it.

 

[TBora]

HBarlow:



I adjusted the brakes overly loose to try and keep them from getting hot when not being used. If B. G. 's diagnosis is correct, after they "Break in" I will then snug them back up per your suggestion.

 

[HBarlow]

I understand and agree with BG's advice. However, if the rear shoes are so loose as to be barely contacting the drums they won't wear in. Only you can determine what you have and the best procedure to go forward.

 

[GAmes]

Our self adjusters are notorious for not working. I would manually adjust them until they barely make contact, then drive and check it again.

 

[JMcCoy]

Did you fit the shoes to the drum? Quite often the tips of the shoes will touch and the middle will not. If this happens, it creates extreme heat because the tips are burning. I had this happen to me. Just set the shoes in the drum and make sure there is even contact. Then grind or sand the shoe so there is even contact. Since the shoes are already installed, You may be able to put the drum half on and take a flashlight to it. You may be able to see the light through the gap. You should also to take course sandpaper to the drum. This will knock the glaze off and aid in the break in. I chased this problem for a long time until someone told me. Now I always check before installing shoes.



As a side note, I would also bleed your brakes with good brake fluid (if not already done so). Moisture in the lines and heat in your drums could give you problems on your trip.

 

[TBora]

OK, I pulled the drums:



1. Primary/secondarys are (always were) in the correct postions.

2. Put a little high temp grease where the shoes rub the backing plate.

3. Visually checked everything.

4. Shoe fit looks good.

5. Tapped with a rubber mallet the shoes a little to make sure they "float".



The only thing that looked a little different between the left and right brakes was that the left brake secondary shoe (longer, thicker, rear one) seemed to be about 3/16 inch further out (3/16 larger radius against the backing plate). By tapping it around, I was not about to remove this increased radius.



I then (as a test), completely backed off the adjustment..... all the way. Then went out for a test drive. Results: Right side drum bone cold. Left side drum too hot to touch.



I am now going to pull the left drum and take another look. I might just "reinstall" the shoes to see if anything is wrong that I can't "see".

 

[TBora]

Forgot to mention:



With both wheels jacked up, I can turn the wheels forwards easily..... but turning them backwards is very hard.

 

[B.G. Smith]

You do have the spring hold downs in the center of the shoes in place with the spring on the outside of the shoe???? Just had to ask. bg

 

[JMcCoy]

Be carefull not to back the adjustment out too far. You may blow out your wheel cylinder.

 

[TBora]

Both spring hold downs are in place (new springs, pins and retainers).



I took the shoes mostly off and reinstalled them. Nothing looks different. The larger radius of the rear shoe still has me worried. It sticks out 3/8 - 1/2 inch more that the front shoe. The extra lining thickness only accounts for 3/32 of that. Think I'll pull the right drum and compare the difference that the rear shoe has ( I know it's smaller, just not how much smaller). But still, I don't know what is making that shoe have a larger radius.

 

[B.G. Smith]

I'm not sure I understand abou9t the larger radius? While you have the drum off, take that shoe and lay it in the drum, its shap/radius should match the drum pretty close, the drum has some wear so the shoe should contact the drum in center of shoe with small clearance on each end.

 

[PMould]

TB. is one ebrake cable sticking,not letting the shoes contract? I would disconnect them and see if they move freely. just trying to help. pete

 

[TBora]

PMould



I think you are correct about the Ebrake cable. Mine is not sticking, but rather adjusted too tight. I went under the bed where the cable adjustment is. It was adjusted max tight. I backed it off about 3/4 inch, then looked at the shoes..... yep, they had moved so they were now centered in the circle that the brake drum makes. Appears that the ebrake cable pushes the bottom of the rear shoe into the drum. Upon release the bottom of the rear shoe should return to the neutral position. With the lack of slack, mine was holding the rear shoe towards the rear, thus making the set of shoes to be centered to the rear, thus my larger "radius" problem.



To much traffic right now to test drive (I would have to use the brakes too much to be a valid dragging test). I will give it a try tomorrow morning.



Without you guys (BG, McCoy PMould and everyone else) I think I would have commited mass murder by now. THANKS!!

 

[B.G. Smith]

TB. is one ebrake cable sticking,not letting the shoes contract? I would disconnect them and see if they move freely. just trying to help. pete

That is a very good point. Look at the top of the shoes where the half moon cutout contacts the stationary round post and see if they are coming all the way back to rest. bg

 

[TBora]

Yes, BG, they are coming all the way back. That is what was confusing me. I could see the half moons were seated, but the whole shoe complex was shifted to the rear. But now with the loosened Ebrake cable the shoes are back where they should be.

 

[TBora]

Just did my test drive and the brake drums stayed cold!!! But..... that is with the shoes backed way off and the ebrake cable very loose. So now I will start adjusting them.



Without rehashing all of the drum bake adjustment threads (I've read them all), do you guys have any special tips?



I plan to leave the ebrake until last... adjust the shoes, then after my pedal comes back up and test drives show no excess heat, then I will adjust the ebrake cable... does that sound reasonable?

 

[JMcCoy]

Jack back of the truck up so both rear tires are off the ground and in neutral. Rotate the drum and tighten until the shoes just barely drag on the drum. It's a little harder on a rear wheel drive truck because you have the weight of the gears to account for. When you do the other side you have to account for the weight of both the gears and the drag of the first drum. It sounds harder than it really is. You should be able to feel and hear hear the drag on the drum. Good luck