Buckshotram

Have any of you guys/girls figured out what was causing your problems??? Mine have been locking up and lots of you were having the same proplems/symptoms I am. Saw lots of talk on "GM wheel cylinders night and day" thread but no updates. Didn't want to bring it up from the grave so here's a new one.

OldDodgeOwner

Mine'll lock up a bit on ice, but other than that, no problems...

Buckshotram

yeah lots of people have had good luck with them, a few people such as my self seem to of exagerated an existing problem.

I think somthing in the abs system is on vaction
Can't seem to get the adjsters to "click" even put new self adjuster on, there were atleast 5 people that were having some trouble I was wondering what they did to fix it???

infidel

The larger cylinders were originally my idea so I've been watching it closely
I've only come across three people so far with lockup problems and can only guess at the cause but think it may be due to weaker front brakes.
Perhaps caliper, hose or 4w ABS, you got me.

95black2615

i have rear lockup problems BAD and all the stuff is new back there. I initially blamed it on the GM wheel cylinders so I changed them out. It still locks up just as bad with new factory cylinders in, so my problem lies elsewhere.

I just got fed up with it and just drive it with caution and plenty of room

Sean Allan

I did the modification of changing out the rear drum brake cylinders to the larger diameter GM cylinders, and I did notice a significant improvement in braking performance. I have not experienced any lockup problems.

Somewhere in this system is a proportioning valve, which controls the flow of brake fluid to the rear brakes. This proportioning valve selects the bias of front braking vs. rear braking. If you are experiencing lockup problems, it could be this is giving you the issues.

It's one thing to do your own body work, but doing your own brake work can be dangerous. Make sure it works right!

Sean.

nickg

I have the GM wheel cyls, and mine stops on a dime, no lock up issues, my prop rod has been lengthened over stock and I can actually have all wheels "lock" so to speak.
I've found that a sticky Park brake cable is usually the issue, if the park brake arm is NOT fully in the release posn, it will cause the brakes to "lock up".
You have to remove the drum and physically try to force the arm back to ensure its fully released

j-fox

No insult meant with this, but make sure the smaller pads are on the front half!

I had a shop years ago do them backwards. They kept telling me to break them in. i pulle dthe drums and they did them backwards.

dj_souvlaki

i've seen that too many times. plus if they are out of adjustment you'll be stuck with a lock up problem.

95black2615

No insult taken I just want them fixed. I know about the small pads on the front, but could have had a brain fart when I installed them over a year ago and didn't think about it.

I'll have to check that.

edcasey

My truck has been locking up for many years. It starts with just locking up the first time I put the brakes on in the morning. A few months later it will start doing it when the road is wet. Eventually, it gets bad enough to be dangerous. What I do is change the rear brake shoes. Once it has new shoes it works great. 12 to 18 months later it starts again and I have to replace the shoes again. It's an endless cycle.

When I pull the shoes of they show almost no wear. They are nearly as thick as the new shoes. Sometimes there are small surface cracks but otherwise the pads look like they should go another 5 years. The last time I changed them someone suggested I use cheaper / softer shoes. We'll see how they work. I'm not sure what causes this but it did it when it was a dually and before I put on the GM cylinders. I can now change the rear shoes with my eyes closed.

nickg

something else to think about, besides long and short shoe issues is that the shoe has a double lip where it rides against the anchor and it needs to be facing outwards, I believe the shoe is also stamped "out" it can be installed wrong, and the shoe will not sit properly against the backing plate. almost like there is a left and right, front and back shoe and they only fit in one spot each, and are not interchangeable

my suggestions to cure the "lock up" issue
1) confirm p-brake arms are physically forced back
2) confirm long shoe/short shoe are installed correctly
3) as mentioned above "double metal part facing out"
4) adjust rear shoes properly....adjust until wheel LOCKS up then back them off till they have a slight drag, any other way and they are not adjusted properly

Russ Roth

Doing that nearly eliminated my lock ups in the wet weather. I take them up a couple clicks (or more) about once a month. Those self adjusters are about worthless.

infidel

What you describe sounds exactly like a common problem in wet/humid climates with most drum brakes, the drum flash rusts causing it to stick.
About the only thing you can do is scrub the rust off by gently applying the brakes in a safe place when you first start up.

Russ Roth

I have a hard time believing that's the reason they do that. My '67 PW has been in the family since new, drums all around and has never done that. Neither have any of the other drum equipped rigs I have had over the years. This is the only rig I ever owned that did this.