What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Brake lock up

R

RIPPEDK5

Guest
I have a 2005 chevy silverado z71


A while back I my rear end blew, and because of money restarints I put a 10 bolt out of an 86 k10 with the same gear ratio in it as a replacement. both had drum brakes, ust had to modify the lug pattern a bit..

anyways, recently my brake master cylinder started leaking (very slightly) and my pedal is acts as though it catches and then doesnt.. but thats not my main issue..

my main issue is the right rear tire keeps locking up on wet days, or if the wheel isnt traveling faster then 5 mpgh,. it does have wheel spacers.

the other side has no issue, and the e- brake doesnt really hold... the brakes are adjusted and the brakes are only about 2 years old (new drums, shoes, hardware etc.)

any ideas?
 
Wheel bearing seal.
Not absoulte, but most likely or else a leaking wheel cylinder.

Either way, you have some grease or brake fluid on the shoes on that side. I suppose the other side could be just not functioning causing all the braking action to go to there, but every time I had a problem with a drum brake locking up, it was grease.

You would think that would cause that side to not grip, but it doesn't.

Look close at the edge where the brake drum clears the backing plate, and you may see some stains.
 
had the wheel off.....no oil, wheel cylinder looks new (cause it basicaly is).

i should note that this is my second drum on that side and this one is bright orange from over heat rust
 
Interesting.
Well, either the other side is not working for some reason, or there is something mechanically wrong with that side.

None of the adjusters on my two offroad truck have worked over the years. The kind of mud I go through just cements the screw adjusters solid. One year I decided to make them work and modified the little plate that turns the screw and did some other mods.
Both rear wheels wanted to grab. Turns out the mods I did made them adjust too much and kept the shoes dragging slightly on the drums all the time.

It really sounds like that side is dragging slightly and getting hot. Its possible that its related to you master cylinder problems. If the other side was adjusted just slightly less tight than that side, and the master cylinder was holding too much pressure to the rear, then it would tend to show up on that side.

What was on there before the rear end blew? I assume it was drums. If it was disks, then that could be your problem.
The fluid handling setup is different from disk to drums. For instance lots of drum brakes setups keep a small amount of pressure on the rear at all times so they respond faster.
Without that, you might feel that they do not catch and then do.
If the MC is leaking, then I would replace it regardless. If it helps with the rear problem, then great.
If not, then you have at least repaired a defective part, and eliminated a possible cause for the rear drum.

One other thought occurred to me. I have only seen this once, on a truck with many miles, but it had the same symptoms.
As you know, modern drum brakes are self-actuating. When the leading shoe touches the drum, the whole assembly pivots and causes the shoes to bind harder, using the force of the rotating drum to help stop the truck.

The edges of the shoes rub on the backing plate as they pivot. On this truck, the shoes had worn a low place in the plate and would tend to hang.
As he applied the brakes, they would not pivot until the force got great enough for them to jump over the ridge.
Then they would pivot all the way and lock up.

He fixed it temporary by putting a film of heavy grease where the shoes slide on the plate.
But he finally had to touch it with a grinder to smooth off the ridge so they could slide.

Make sure yours pivot easily.
 
Here is my exact setup on the truck..


previous axle on the truck was a 2005 3.42 gear 10 bolt with drum brakes. the brakes were one with that "W" style spring set-up..

the axle in the there no is out of a 1986 chevy k10 with now 100k on the axle.

within the last 2 years i replaced the drums, shoes, hardware, wheel cylinders, axle seals, diff fluid, diff cover, brake lines...there are pics in my profile of it.

on the axle in the truck now there are wheel spacers on the axle...torqued to spec. the axle studs were replaced and machined out to the newer style studs, (thats on both sides)
 
Well, there is something wrong.
I'm down to a slick tire on that side.........

Anything in the history give a clue? Did it start as soon as you put that axle on, or later?

I'm not as up on GM stuff as other brands, but I have worked on a few. I would have to actually see your brakes to put a face to that model.

I suspect that something you put on was either bad or failed after you put it on.

There is one old mistake I used to see a lot. Not even sure if any system even does it anymore.
But at one time, there were two different brake shoes per side. They came in a set, and if you got them on wrong, things got weird.

I put a set on wrong on my old Jeep one time, and one side kept grabbing and the other side would barely work.

The shoes look about the same, and will fit both ways. But one has less material than the other.
Its been a few years, but I think that the shoe with less material went on the side facing front.
If you put the more material shoe on front and the other on the rear, it would grab.

I don't remember seeing one like that lately, but they may still be around. My experiences have tended away from brake systems in the past few years.
 
I will have to retake the tire off again.. i am beginning to think that the drum axle flange relation has something to do with it. since i put wheel spacers on and torqued them properly; the center of the drums pulls into the flange center..

(hard to explain: but if you grab a drum and pull the drum apart with your hand and press in the center with your thumbs--best i can describe it)

and the holes being drilled larger on the drums....could they have something to do with it? (i have no road vibration)

how ever i am also thinking i have 4 rear shoes on the truck because they were all the same size (i know what your saying--one should have less shoes then the other)
 
Well, I don't see how the spacer or the hub could make a difference, but when you have a problem with no obvious cause, you always look at whatever is different.

My problem is, while I have tons of general knowledge about brake systems, and have seen lots of weird problems, I probably have not seen a setup like yours since about the time it was new, 26 years ago.
I've got a real good memory, but I have seen a lot of brakes since then.....

If you take it back off, post some pics. Not only will help jog my memory, but someone else might see something wrong.

As for the holes being drilled bigger, I don't see how that could affect anything unless the drum were running off center, and you would have a vibration then.

I'm guessing the spacers are for wheel clearance. Any chance of finding a couple of wheels and tires that would let you run the back axle without spacers for a little while to see if anything changes?
 
I have been trying to find wheels that fit without spacers and its not working well...

Its the later lug style (2000+) and the older flange, which is different

cant use the older style rims, cause the wheel lugs dont fit, and the newer rims dont fit the center hub flange..... grrrrrr

I would just put the right axle in if it didnt cost $2k+ to install a used one

This is so F'd up

yea I have a serious tire to leaf spring clearance problem, since the older style axle about 3" narrower on each side, so a spacer is mandatory and even with a 1.5" spacer i am only about an inch of clearance

i will have to find a time to retake the tire and drum off...The drum is EXTREMELY hard to get off because the center hub section of the drum clamps itself to the axle flange from the wheel and wheels spacer forcing it flat on the axle flange... it might be a few days
 
when you take it off, get a grinder or dremel out and clearance things a little. Couldn't hurt. Stuff shouldn't fit that tight and could cause a ....... "problem". But I'm just shootin in the dark.
 
Yep, I was going to mention that. If the center hole is too small, it needs to be enlarged.
Problem is, especially with larger lug bolt holes, that center hole might be the main thing keeping the drum centered on the axle.

If you know anybody with a machine shop, it would be best to have them turn it out larger on a lath or a milling machine with a fly cutter so that it stays centered.
Just turn it out just enough for clearance, Clarance, not enough to get it sloppy.
 
Normaly i do knock off all the edges on the shoe. and if the drum has a lip, i useuallytake the lip off..

but i will use that that though.. I plan on going back to the original old chevy bolt pattern and getting different rims (for a SAS), but thats not for a while since I have to get all the parts first, and get new/ used rear axle shafts
 
You must log in or register to reply here.

Latest Posts

Top Bottom