Another brakes question

[Gene]

Finally got my brakes bled, and I have a real firm pedal. But the problem is that they wont lock up or they take a bit to stop even at low speeds. I looked at the rotors on front and they have some rust on the surface, but no grooves at all. This is the first time these brakes have been used in awhile as I got them from a truck that I traded for that hasnt been on the road for awhile. So should I just have the rotors turned and the drums and replace all the pads even though they have alot of meat left on them?

[cdowns]

i'd just go over them with a course scotchbrite pad // the discs and drums as well as the pads and shoes

[JimKshortstep4x4]

Do you have power brakes and will all four wheels lock up on gravel? I would suggest staying with the pads and rotors for now. It almost sounds like one set of wheels is not being braked or the power booster is not working, (assuming that you have power brakes.

If you have a four by four with the 1/2 ton booster on it, changing to a 3/4 ton booster works wonders!

Jim

[Gene]

Originally Posted by JimKshortstep4x4

Do you have power brakes and will all four wheels lock up on gravel? I would suggest staying with the pads and rotors for now. It almost sounds like one set of wheels is not being braked or the power booster is not working, (assuming that you have power brakes.

If you have a four by four with the 1/2 ton booster on it, changing to a 3/4 ton booster works wonders!

Jim

Yep, I have power brakes and I know the booster is working. I have jacked up the front and back and spun the wheels and had my daughter hit the brakes, front and back are working(somewhat).

I failed to add that the differentials are from a 91 suburban. Could this add to the problem?

Originally Posted by cdowns

i'd just go over them with a course scotchbrite pad // the discs and drums as well as the pads and shoes

Sound advise, thats exactly what my dad told me to try

[JimKshortstep4x4]

It is hard to believe the later differentials can cause a problem unless the wheel cylinders and calipers are a lot smaller.

Which prop valve do you have on your truck?

Jim

[Gene]

Originally Posted by JimKshortstep4x4

It is hard to believe the later differentials can cause a problem unless the wheel cylinders and calipers are a lot smaller.

Which prop valve do you have on your truck?

Jim

Stock prop valve from a 2wd 71 Chevy. My truck is 4wd now.

[Gene]

Ok, changed master cylinder, bled brakes again(no air in system). My brakes still will not lock up on dirt or gravel but they will stop eventually. What do I try next? I tried lengthening the adjustable rod between the booster and the master, helped but still no lockup.

[Sammy]

Let me throw this out there. You can have a restriction internally on the front brake hoses. They can look fine on the exterior but have internal failure causing limited stopping in the front where 80% of your stopping would be. My bet would be to replace the front hoses and re-bleed the system.

[Gene]

Originally Posted by Sammy

Let me throw this out there. You can have a restriction internally on the front brake hoses. They can look fine on the exterior but have internal failure causing limited stopping in the front where 80% of your stopping would be. My bet would be to replace the front hoses and re-bleed the system.

Well, all the brake lines front to back are new from inline tube. I bought the front ones new also. Any other ideas?

[fastwillie 696969]

i would clean the pads up with emory cloth.clean off the rotor surface and take the truck out and slightly apply the brakes ,like power braking get the pads to break in ,there is some quite brake and stop pad you can add to help the pads ,the graphite some time just glaze the rotors and pads .try getting them to set in

[biggestjohn]

Check to see if you can push in the pin on your prop valve. ( actually its a combonation valve ) My B-I-L had a simular problem, turned out the pin was stuck.

[Autoblueprint]

Originally Posted by Gene

So should I just have the rotors turned and the drums and replace all the pads even though they have alot of meat left on them?

Seems like pads/shoes are glazed...if a good, hard round of scotchbrite/emery cloth all around improves braking response...then the pads/shoes were glazed...and will glaze up again...so...machine rotors/drums, replace pads/shoes and install new brake hardware ( pins and o-rings for the calipers and spring kit for the rear ). Then flush/bleed the brake system again.

Might be a good idea to overhaul calipers/wheel cylinders too.

[Gene]

Originally Posted by Autoblueprint

Seems like pads/shoes are glazed...if a good, hard round of scotchbrite/emery cloth all around improves braking response...then the pads/shoes were glazed...and will glaze up again...so...machine rotors/drums, replace pads/shoes and install new brake hardware ( pins and o-rings for the calipers and spring kit for the rear ). Then flush/bleed the brake system again.

Might be a good idea to overhaul calipers/wheel cylinders too.

Ok, sounds like a plan. Thanks guys.

[Wrenchbender Ret]

Some of the brake linings we get now are really hard since they took the asbestos out of them. My 70 with disc brakes wouldn't stop good at all. I put Ceramic pads on the front & got new shoes for the back from Carquest & they work good now.

[Gene]

Here's another question for you, the differentials came out of a 91 Burb, with antilock brakes. Is it possible that the calipers are not set up to lock? I have no clue how anti-lock systems work is why i'm asking. The brake booster and master had an anti lock system on them when I took the burb apart???

[D.PASSMORE]

Still working this issue? I don't think the anti locking portion has anything to with the brakes actuating if you have it set up like a '72 brake system. For anti-locking - it has to with the amount of constant pressure pushed through your lines to the actuator. My .2 cents . I'm having the similar problem on my 4x4 Balzer. Stop's straight, but will not lock up the 33's (any wheel) on hard pan. Everything is brand new. I'm looked at the pads/shoes today and I believe its the material/composite. This stuff hardly leaves dust.
I'm thinking about replacing with creamic too.
DP