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HB problem found. Not HB problem rear drum problem.

Air in the hydrabooster (powersteering lines) can cause a little pedal kickback almost like a warped rotor. Usually goes away after a couple of days (or at least it has for me :D ).
 
I miked the rotors and they are true. It feels like the front end wants to jump out from under the truck but only when the brakes are applied, almost like anti-DW. I did not take long to bleed the booster after I put the HB pump on. Did you drive yours like that? It feels really bad. Can notching and boring the orifice cause the booster to pulsate hard enough to cause this? Or will a bad booster do this. I would think that a bad booster would have weaker braking but these stop fine. I also think that my front end is toed out as the truck wants to wander down the road. We also measured and it measured toe out by about 1/2". I also need to adjust my draglink to center my steering wheel (prolly not part of the problem).

Help me please.

Ira
 
"I don't think that it would drastically change the kingpin pre-load unless the whole truck was bouncing around. It would however cause the truck to drive all wierd.
It is most likely due to a toe problem.

Air is the prop valve? You mean the one under the radiator area? why do you think that air is in there. It is more likely that you have air in you calipers as they hold much more fluid.
Either way I doubt that air would cause any pulsations. It could give you the low and soft pedal though.
The number one cause for low/soft pedal is that the drums are not correctly adjusted, so the pads have to travel too far to get in contact with the drums.
The pulses could be due to two things.

1. Warped or non-paralell rotor faces.
You have already ruled out the warpage, but did you check both sides of the rotor for too much runout?

​
2. This one is a strech but bear with me here. If the wheels are hopping back and forth due to a toe issue then the calipers would be doing the same just not as much movement since they "float" on the rotor. This "float" and the cailper movement in relation to the rotor face to cause the caliper to pump fluid back towards the MC. Much in the same way that a warped rotor will.

Get your toe in spec and see how it goes. Remember that D60's are pretty sensitive to toe changes. With 37's on 15" wheels I would shoot for 1/8 in or even a little more."



I am hoping it is a toe issue and not the booster or MC:doah: . If it is not a toe issue I think I am going to buy a MC and HB for an 87 V-30 as that is the brake system I am running.

Ira
 
can rotors warp from the weight of a 60 sitting on them.....

YES (but you checked that)

As far as the shimmy, the toe in or out can have alot to do with it, lack of steering stabilizer, I didn't see your lift and tire size off hand but lack of caster can give it a floating sensation, and even unbalanced tires can really wobble a good bit, and even trigger death wobble.
 
The wierd thing is it only happens when I brake. As long as the pads are not touching the rotors there is NO vibration at all. I run 37 MTRs it is in my sig. They are balanced with airsoft pellets. I dont think it is the pellets either as the tire has no time to slow before the shaking starts it is almost instantly as I apply the brakes. I run crossover and I do not have a stabilizer on currently.

Ira
 
sandawgk5 said:
I give it gas and it moves but acts like the brakes are on. We take it down the block and back and all works fine other than the grinding sound of the pump and the rapid stop due to dragging brakes. We park it get out and the rotors are HOT.
Click to expand...

When I read that, I though that you could have warped the rotors. But later on you said you checked them:confused:
Unless you checked them first, and got them hot & warprd them afterwards.:doah:
You were asking for feedback, but thats all I got.:dunno:
 
Rotors are def out of the question now. We took the front end apart to mic the rotors on both sides and found what looked like oil contamination on the rotors. There were spots that looked like hotspots on a flywheel almost. For electrical types it looked like oil contaminated brushes on a slip ring how it leaves that film.

Well we took it all apart and turned the rotors to clean the contamination off and replaced the pads incase they were contaminated. We did not have time to adjust the toe and it still had the same vibration problem. Now I have a new problem on top of it all. Apparently the passenger side brakeline is leaking. There is maybe 10 miles on these and they are procmp stainless lines from ORD:mad:. I guess I am gonna go get cheap rubber ones if they are gonna blow out and save my money. I thought I had a bad MC cause the pedal went to the floor, I could pump the pedal and get it back but then it drifted to the floor. Upon further investigation it was discovered the brakeline was leaking. It is either the toe casing the issue or a bad boosterrr. I dont even know if the booster can cause what is happening. I am lost.

Ira
 
I agree with getting the toe adjusted as the next step. I run about 3/16" of toe-in with 39.5's and it runs down the road pretty straight.

Rene
 
I'm with Rene on this one ... granted, my truck is very different, but when I did crossover and botched my toe setting by measuring tape, I had crazy wheel hop and the truck wanted to jump around something fierce. It doesn't take much to make the front suspension all wrong, so I'd say fix that first.

-- A
 
Well I set the toe and still have the same problem. Tie rod is old could it be the tie rod ends? Once again it only does it while braking.

Ira
 
Another thing, I measured my castor by placing my angle finder on the bottom of the knuckle by the kingpin and also by placing it on my ORD crossover arm. Both of these places measured 10 degrees. I think the spec is 6-8 could this also be causing the problem? I am trying to think of all things that it could be before I replace the MC and Booster.

Ira
 
sandawgk5 said:
Well I set the toe and still have the same problem. Tie rod is old could it be the tie rod ends? Once again it only does it while braking.

Ira
Click to expand...

Any wierd movement in the TRE's when the steering is cycled?

Rene
 
Want me to measure my castor in the same way? I think that i am parked on a slight hill though. What part of the truck did you compare the 10Deg measurement to....if any.
Is Roz's driveway at 0Deg? I doubt it is.
 
I did not think of that:doah: . His driveway is sloped to the rear so the castor is prolly good. I was doing this by myself and could not see the tierod. I will be out of town until Tuesday so it will have to wait until then. I should measure it again as my parking spot is level and the truck is at my house now. I had a problem with the steering felt like it stuck and I had to pull the wheel quite forcefully and it felt like a slight pop and then it would turn again. Hopefully unrelated. This is really confusing and frustrating. Maybe I should put my vacuum booster back on and see what that does. That will atleast tell me if it is the booster or not. But I dont have the Hi pressure hose from the pump to the steering box it was damaged upon removal. Well I will get back on it when I return from Skiing.

Ira
 
OK I checked the tie rod and all is tight. It is nice not having inner fenders:D . I just reached in and turned the steering shaft ( with the engine running of course) and looked at the tierod there was no slop in the TR ends. The Draglink/pitman arm and crossover arm are all brand new as well as kingpins bushings and springs. Kingpins looked OK and they are preloaded with a fender washer. I am still having the problem only when brakes are applied so I am beginning to think that my problem is not a steering issue. Does anyone now if a bad booster or MC can cause the problem I am seeing?

Thanks

Ira
 
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