Shuddering brake pedal.

[Blue95]

Air/ contaminents, if they have never been bleed or new fluid put in then that could be a strong possibility.

 

[canuckz71]

I doubt the fluid has ever been drained. I will start there with new brake fluid and bleed the system and if that doesnt work ill tae a look at sewlows suggestions. Thanks guys.

 

[sewlow]

Brakes with ABS can be a major pain to bleed if you get air in the system, especially after a caliper or cyliner change. Be prepared to go around them 3 or more times.
The rear adjustment is no fun, either. Due to no adjusment holes, or even knock-outs provided, you have to remove the drums & adjust from the inside. Too loose will not give you a good pedal feel, & causes the rear brakes to make strange sounds as they engage & release. Too tight will cause the drums to warp from the heat caused by the extra heat that that generates.

 

[TylerZ281500]

has anyone ever noticed the little bleeder on top of the abs valve? or i should ask is that what that thing is for?

 

[Fobroader]

Hey man, have you ever replaced your shocks?? On my old truck, before I got my shocks replaced the ass end used to chatter all over the road if the road surface wasnt perfect. After I changed my shocks the truck braked a lot straighter and wasnt nearly as terryfying at highway speed when you stomped on the binders. I got my rotors, drums and pads from Parts Source, they were mainly the Nascar branded stuff, I really liked the stuff.

 

[JAW's]

When replacing the rotors & drums, I have the new ones turned right outa the box. You'd be surprised at how out of wack they can be, even when new.
I've also found both my trucks to be finicky about wheel nut torque. DO NOT tighten them down completely with an impact.
Only because I have access to brake lathes, & a hoist, I did an experiment when I had these same probs you're having. And I've had 'em, to the point of doing complete brake jobs 2X in a month, trying to eliminate the shuddering.
Tightened the wheels with an impact the same as if a 'pro' tire shop might, right after a brake job, which included turning of the drums & rotors. Drove it 100 miles. The shuddering returned with a vengence!
Pulled the drums & rotors off, & threw them back onto the lathes. ALL needed to be turned to make 'em round again!
When it was all back together, I used a torque wrench to snug the wheels down to 100lbs, then went around 'em all again, torqueing the wheels down to 110lbs, then once again to 120lbs. Yea. I know, just a bit **** retentative, but since I've followed this procedure, the shuddering has been all but eliminated.
I've had tire guys say that this is not required. They've told me that their impact gun was just calibrated (?), or that the 'torque sticks' on the gun are infallible. I don't care. I say use a torque wrench or stay away from my wheels!

SSBC is the only Co. that makes their own rear disc set, that matches their front big brake kit. All the others that I've found make their own big brake kits for the front, but the rear is cobbled from various off the shelf G.M. parts. Not saying that that's not right, or that they won't work, but SSBC's R&D is a bit more advanced than the average 'do-it-yourself' guy. They've developed a specific set of rear brakes for a specific vehicle. And that R&D time ain't cheap!
The advantage to that is having the confidence in your brakes backed up by a respected manufacturer. Piece of mind.
Aesthetically, I like the idea of matching rotors & calipers peeking out from behind the 20's!
But I still haven't made the leap to an aftermarket big brake kit, because like you said, damnnnn, those things are freakin' expensive. The complete four corner system that I've been looking at for a long time, is $3500.00!!! That's more than what I paid for my whole '97!

If you do go to an aftermarket rear disc system, remember that most require a wheel size of 17" or larger.

Torquing down your wheels IS essential. If you tighten them too tight then you will warp your newly instaled rotors. Warped rotors will cause the exact symptoms you have been expiriencing. Alluminum wheels are always torqued a little tighter than steel wheels. I run my Aluminum wheels at 130 foot lbs.

The shop I work at hand torques every wheel that goes out the door... the way it should be done.

 

[DGA1]

The owners manual for my '96 GMC K1500 shows the correct lug nut torque to be at 140 ft. lbs. This is what I stick to.

When reinstalling the actual drum part of the brake, it needs to slightly touch the shoes and drag a bit. From there on out put the truck in reverse and hit the brakes hard, this will cause the automatic adjusters to actually adjust properly. Other important thing is to take the adjusters apart and grease them so they operate as the are designed. Rusty, sticky ones will not do you any good.

 

[canuckz71]

Is there a way to tell if the rotors are warped?? I dont have a torque wrench or air impact so i just use a tire iron to tighten all the wheels. Not sure if i couldve gone too tight.

Eugene, I replaced the shocks about 2 months after I bought the truck and I've had it for about 2 years. The truck did the same thing yours did and this seemed to solve that problem but the braking seems to be a different issue.

 

[DGA1]

Put a run out gauge on them and spin them. The low brow method is to tape a screw driver to a bucket, so it will not move. Put the bucket with the screw driver next to the rotor, just a hair of it touching and spin the rotor...if it's warped a good amount it will touch the screw driver at some points and not on others. I do this with my track motorcycle to see if I've warped a rotor after a significant crash, it works reasonably well.

 

[canuckz71]

Alright thanks for the info, I'll try the screwdriver and bucket method.

Won't have much time to look at it for a while until schools done which will be near the end of the month. I just have no tools or place to work while I'm at school.