1999 C3500 Steering and Brake Issues

[GM Guy]

Hey all,

Got the 99 C3500 back on the road, Fluidampr, PS pump, Water pump, motor and trans mounts, pulley damper, tensioner, deep radiator cleaning and fin straightening (the most time consuming of all ), t-stats, paint battery trays and acid damaged paint on inner fenders, new washer tank and pump, etc.
Made it from KS to Little America, Wyoming with no powertrain issues so far.

But, a problem it had before with the steering and braking is still here even after a new PS pump.

It seems to pull fairly hard to the left, then all of a sudden, 100+ miles down the road, it quits pulling and tracks relatively straight. is this an issue in the steering gear?

Also, the braking is weird. the pedal seems to vibrate/ rumble (hard to describe the sensation, not really a vibrate, but it is just not "solid") as you press down, feels spongy, and will go close to the floor if you lean into it. before the new pump it would go to the floor.

One thing worth noting is the loop line that follows the front crossmember to supply the Right front brake is mangled to shit, but it still seems to brake and release fine and doesn't leak, so I doubt its closed off.

I have never flushed the brake fluid, and I dont recall the ABS coming on.

I need to get a temp gun to see how hot its getting, it may have an issue in the box with a sticky valve and causing the fluid to overheat.


So, what does the PS issue sound like? I am stumped on it.

What does the braking issue sound like? I am leaning towards a good line from a junkyard (in Idaho, 8-10 inches of precip a year, original brake lines bound to be good. ) and flush as much as I can myself, then possibly take it to GM and have them flush and get the Tech II involved to bleed the ABS. By "flush" I of course mean run a bunch of new fluid through till it cleans up, no weird cleaning chemicals or anything like that.

Any input greatly appreciated, as it will be headed to California in a week or so with a cornheader. Luckily the saving grace may be the Tekonsha P3 controller on one of our newer trailers with great brakes.

 

[ak diesel driver]

Sounds like a sticky caliper may be the root of both issues. The weird pedal is probably a slightly warped rotor, probably from the caliper sticking

 

[schiker]

I like the above post better as hot brake fluid might be causing some fade too and low pedal. Compare thickness of all front brake pads.

But might check ball joints too.

If flushing brake fluid try a Motive Products power bleeder if you haven't yet. They sure make it easy to flush out the old brake fluid.

 

[GM Guy]

Schiker, how spendy are the power bleeders? got a link?

I will pull the front wheels and check the brakes over, likely will pull the calipers and lube the shit out of the slider pins. Probably should change that line too.

Does it sound like I have air in the system as well? Debating if letting GM bleed the ABS module with the Tech II is worth it, or a waste.

Thanks for the replies!

 

[Burning oil]

As to the soft pedal, Sounds like air.

 

[schiker]

Might be air or tired master cylinder if low pedal all the time but if it goes down farther after driving then fade related I would think.

http://www.motiveproducts.com/ I can't remember what I paid. A quick search on Amazon is $80.

Should be able to google for it. Also, can find videos on youtube key words Motive Products bleeder. Should find them at Jegs, Summit, and Amazon (where I bought mine iirc).

After you have one it seems simple. You could probably fab one up with a pump up sprayer, a old master cylinder cap, a few fittings and some hose ($30-40 ???). Maybe add a block of wood 1x4 or piece of flat metal and clamp (to reinforce and seal the old MC cap).

One thing to watch out for using a Motive bleeder is clamping the top down on the master cylinder. It can stress our style tank grommets. I think I used a combo of the chain clamps and a couple of medium size carpenter style slider clamps or big C clamp (not a real heavy one) just to help hold it.

I replaced my hydro booster and master cylinder and it worked great to flush the lines / bleed the air as a one person job. I did not have to get a tech 2 to bleed the brakes and they were much improved. But I did not have a problem before and did not open the lines except at the master. I bench bleed the new master also so it was really minimal air contamination.

$80 seems high but I saved so much money doing the hydro booster / master myself it more than paid for the bleeder the way I looked at it (in my case).