brake problem

[67chevtruck]

i have a 67 k10 that i put axles under out of a 76 suburban with front disks and when i drive my truck for a little while and am using the brakes the front brakes will randomly not release when i let of the pedal does any one have any idea what is going on thanks

[silverstreak]

It could be some rust / debris in the master cyl or brake line. I've even seen a brake hose do this. The inner layer of rubber in the hose came apart and blocked the fluid flow back to the master cylinder.

[68gmsee]

When you say randomly, does that mean that most of the time they work fine and other time they don't?

If your brake pistons/calipers are defective such as rusted they may not move freely to allow the brake pads to retract. I would make sure they are properly lubricated first.

Another thing that comes to mind is the rubber brake hoses being collapsed internally and restricting the fluid from returning. They are notorious for doing that on these old trucks.

[67chevtruck]

when i say randomly i mean that when i use the brakes alot and i will let of the brake pedal but sometimes the brakes wont disingage. but the calipers rotors and pads are all brand new the master cylinder, proportioning valve and brake lines are all off the suburban

[WIDESIDE72]

Did the brake parts you used work OK on the Sub? I would lean toward brake hoses.even though they may look OK on the outside, the inside could be broken down.

[JimKshortstep4x4]

Have you tried bleeding the calipers when this happens?

If there is not enough clearance beteen the brake rod and master cylinder, pressure can build up.

Jim

[Wrenchbender Ret]

I'm with Jimk. If your rod from the pedal to the booster or the rod from the booster to the master cyl are adjusted too long it wont let the piston in the master cyl. come back all the way. If not that its probably the rubber hoses.

[67chevtruck]

thanks

[mbgmike]

Originally Posted by WIDESIDE72

Did the brake parts you used work OK on the Sub? I would lean toward brake hoses.even though they may look OK on the outside, the inside could be broken down.

That what I would first suspect. Do a drip test. You should get the same fluid out of both lines. The inner liner collapse on these hoses and most people do not change them very often as they should.

[chas350]

If there is a little air in the calipers they will not release fully. did you bleed the line or the bleeder on caliper?

[AH619]

I fought this once and found that the rod in the master cyl was too long. I installed thin washers under the 2 ears of the master cyl. Test drove the truck too find the correct combo, then remove that much of the rod and problem solved. I dont know if this will fix your problem but 5 minutes and 2 flat washers will tell you. Marvin