Brake Drum Nightmare!


Grug
01-13-2008, 07:15 AM
Well, I got the parking brake working. Nice and snug now! However, I pulled the back drums off as the truck is going for its annual road worthiness check. I decided to change the brake shoes as they were 'questionable'.

No problems getting the drums off by turning the bolts into the face of the drum which pushed the drum off the hub...very slick! Then I installed the new shoes after turning the adjusting star down to it lowest point.

Then the fun began! It was almost impossible to get the old drums back over those new shoes! I tapped, I smashed, I wiggled! I finally got one wheel back on. It was so tight you couldn't turn it by hand. But it was on! The other wheel I finally just gave up on using the new pads as I simply could not get the drum over those new shoes! I ended up using two of the older shoes on that wheel (the two best ones). I know your supposed to change barke shoes by the axle and not one wheel at a time, but there was no way that drum was going over those new shoes.

So, what did I do wrong? Why was it pretty much impossible to get that old drum over those new shoes! I can't even begin to think what it must be like to put a new (unworn) drum over new shoes!

Finally, one brake cylinder was frozen so I replaced it with a new one. That was by far the easiest part of this whole job. I'm gonna' bleed the brakes today which should go easy as I bled them last summer when I replaced the front brake pads.

Advice? Suggestions? Anything?

EA6BMECH
01-13-2008, 08:02 AM
Not too sure if this will do ya any good, but try cracking the bleed screw. It might let you compress the pistons a little more, but ya gotta bleed it.....I know, that's a no-brainer. With that said, do you have slack in the adjuster? If not, then cracking the bleed screw isn't gonna help you. Try putting the old shoes back on the other side, wheels back on and run it around the block. Sometimes stuff just needs to get seated. Then jack up the rear and see what you have. Not the scientific answer you might want, but worth a try.

Grug
01-13-2008, 08:11 AM
Yes, I gave that a try. Not only did I fully remove the bleeder screw, I even removed the brake line from the cylinder. I wanted to be able to compress everything as much as possible. It wasn't too bad as I had to change the brake cylinder anyway.

Now, I've been poking around the Internet and a coupla' sites have talked about a ridge of rust that will sometimes form on the lip of the brake drum and will prevent a smooth installation. I can't say that I looked for or noticed any ridge of rust on my drums. I might have to go pull a drum off (the side where I used the old shoes) and see if there's any rust on the lip.

I've changed brake drums on old VW's, my old Chev half ton, a Jeep Cherokee and a Dodge Caravan and I've never had problems like this (installing drums over new shoes).

EA6BMECH
01-13-2008, 08:33 AM
I just did my Nissan brakes and had the same problem. I never turned the drums, truck is too old and rusted.

G.A.S.
01-13-2008, 09:13 AM
here is your problem.
first off you adjusted the emergency brakes first, those get adjusted last. There is a (strut rod) that connects the two shoes together and is used for applying the emergency brake. You now have the emergency's over adjusted. hence the drum not going over the shoes.
If both your wheel cylinders are functioning and the strut rod is removed, the drum will slide right over the shoes. that method is used if the emergency cables are frozen so bad you cant take out the (slack) to get proper adjustment, OR the drum over the shoe.
If your emergency brake is not adjusted last, you will have a soft / low peddel. Most people keep bleading the brakes to try and get rid of this problem. wont work.........
Now;
The shoe has a resting point above the w/c, with that in constant contact the adjuster can now be used to snug up the shoe to the drum. I like adjusting the adjuster and sliding the drum on and off untill I have a snug fit. If there is a lip on the drum, get it close.
Then with the tire on, (this has the drum in it's fixed posistion), you can do your final adjustment.
Do this on both sides and now adjust your emergency brake.
You will be good to go.
I saw in another post that bleading the brakes when doing a brake job was a no brainer. Only if taping into the hydraulic system.
If your just doing shoes, or pads, there is no need to bleed the system as you have not done anything to allow air to enter the hydraulic system.

Grug
01-13-2008, 01:43 PM
Ok, GAS, you seem to be making sense so far. You're right, I did adjust the parking brake first; then tackled the drums and shoes.

So, if I totally 'unadjust' the parking prake or in other words, basically disconnect it where it 'Y's' under the centre of the truck, I should be able to slide the drums on no problem? Does that make sense? It's no problem to disconnect the parking brake at the adjusting point under the centre of the truck.

But, what about this? When the parking brake is released, shouldn't that release any tension on the back drums (regardless of how well the parking brake is adjusted)? I'm going to assume that my parking brake cables aren't frozen as I was able to adjust them up quite snugly.

Grug
01-13-2008, 05:25 PM
Well, problem solved! Woohoo!

I disconnected the parking brake at the adjustment point and I lightly sanded down the outer lip of the drums and sure enough those drums went over the new pads without any pounding, smashing or cursing!

Then, I reconnected the parking brake, bled the system and went for a drive.

Cheers and thanks to those who replied!

EA6BMECH
01-14-2008, 05:43 AM
Hmmmm.....even I'll admit that the EB was AFU on the truck. Had it all the way tight cause the cable stretched over the years. "I thought" that it wasn't playing a part in the scenario but sometimes it's that "forest for the trees" thing.

G.A.S.
01-14-2008, 06:26 AM
Ya know, if there is ever a time when you go to do a brake job and cant get the drums off, 80% of the time it is the emergency brake that is keeping the drum from coming off. 10% is the lip that gets formed in the drum. and the last 10% would be a frozen wheel cylinder not allowing the shoe to retract..

The theroy for emergency brakes is: If you dont use them every day, Dont use then at all.
think of it this way, when the emergency brake is applied it is no different than pressing on the brake so the shoe is going to grab the drum. A rusted/non used cable wont retract when applied and released, Just like driving with the brake being pressed. It wont free up untill the shoe would wear into the drum.
I have also found that when the drums are off and before you start to remove old shoes, you take a flat pry bar and pull back on the swing arm that is connected to the shoe. This will pull on the emergency brake cable and release it. Might have to loosen that adjusting nut for the cables at this point to achieve full unadjustment
saves from dealing with this issue.

Add your comment to this topic!