truck hopping when on the brakes?

[benoit454]

Hey guys and girls, I got a uqestion for all of you.....

I have an 84 c10 all original as best I know.

it's had this hop to it ever since we got it, everytime you hit the brakes it sorta shimmies and shakes, or basically hops. Always seems to feel like it's coming from the back. My old man said if it's back brakes you feel them through the whole truck, and if it's front brakes you feel them in the steering wheel or pedal. he doesn't feel them on the wheel or pedal, just the whole truck hops. Sometimes it seems worse under slow brakeing or light pedal.

Well we checked it out, found the passenger side wheel cylinder busted, front shoes on both sides worn down way more then the rear most shoes. The driver's side front was worn past the top rivet.

So we put on ONE new passenger side wheel cylinder, had the drums turned, and bought new shoes. We figured that fix it but it didn't. it's not as bad, it used to pull you into traffic, but now it just hops, sometimes not as bad as before, others just as bad.

Another weird thing that happened was monday, memorial day, was when I done this, bled the rear lines, kept getting this spurt when I'd crack the new one loose, then a solid stream of fluid, no matter how many times I did it.

I do the two man job, one pumping, then holding, other taking bleeder loose, and tightening it when they hit the floor.

Well we got a good hard pedal, and left it alone. Started it up tuesday, moved it out of the carport, hit the brakes, pedal kept moving slowly down after hitting what I thought to be the hard spot and where they'd start working, truck kept rolling, pedal dropped very slowly to the floor.

So I tried re bleeding them today, same thing the new one kept spurting at first then a solid stream, the old one as soon as you cracked it loose it just be s solid stream out of it.

Pedal is better, but not full, maybe 3/4 or better.

Front brakes haven't been touched, pads are probably half gone maybe a little more. So I figure maybe that's the 3/4 pedal problem.

Any ideas on not having a full pedal?



The main question is the hop, why would it do it? Would it be my rotors bad? I'm going to have them turned and put on new pads, probably sometime soon. Right now we have to drive it, I got the interior out of my car dyeing it. So as soon as I get that finished I guess it'll be front brake time.

Any thoughts? would it be front brakes casuing the shaking/hop and not having full pedal?

Or maybe where I changed one wheel cylinder and not the other?


Or are they still seating and not fully seated yet? We did drive it today, maybe 10 miles round trip or little more.


Oh one other thing, I noticed on this truck is doesn't have the small canister in the power brake line. it's the one in the vacuum line going to the back of the carb. The 86 4x4 did, and my car does, as well as many others I've seen. yet my 86 camaro didn't and neither does this truck.

[Mickey_D]

One way to definitely determine if it's the rear brakes, on a deserted stretch of vacant road take it up to about 15-20mph and gingerly use the parking brake (while holding the release handle out) to stop the truck without locking the rear tires up.

If you get the same symptoms, you know it's the rear brakes. If the truck just slows to a stop without any shakes or anything, you know it's something with the front brakes.

[FlatBrokeRacing]

Just a friendly word of advice here:
Any time you replace one wheel cylender, replace the other. The reason I say that is because both rubber seals (on both sides) are the same strength.
Another thing to make sure of is to have the rear brekes adjusted properly.(it makes all the difference in the world on pedal travel). The best thing to do next would be to replace all the rubber in the braking system.(all rubber brake lines, and wheel cylenders)

Just trying to help out...
The main objective is safety... when it comes to brakes, it is not only your safety but everyone elses safety around you as well.

Hope this helps you.

[benoit454]

Yea no shyt lol. If it don't have good brakes or steering I won't get in it let alone drive it.

I'll have to give the e brake a try.

I kno I should have replaced the other but you know when money is tight, it'll probably end up being changed, new bearings, seals, rotors, pads, and calipers in the front pretty soon.

The brakes are adjusted properly I have the measuring tool you extend out to fit your drum, then tighten the nut to lock it in that length or distance, then adjust your brakes to that distance. One side fits in the drum and the opposite fits over the shoes.


Now we have another problem with the truck though....

se this thread for more info....

http://67-72chevytrucks.com/vboard/s...82#post2202882

[benoit454]

Hey all I checked it out better today and the whole front end is very nice and tight, ball joints, tie rods, and pitman arm, as well as the idler arm.

I did however find some slop in the driver's wheel. I took it apart and the cotter pin was broken and the nut came off by hand. The bearings had no preload at all on them, so I repacked them and reinstalled as they should be.

You guys think that may have been the problem? I gotta take it out later and see if it's better.

[xtreme80]

Could be the problem but most likely not. I'd be willing to bet that if it IS coming from the rear, you have bad drums. Those can only be resurfaced so many times before they wear out completely.

As for the pedal slowly going to the floor, that sounds like a bad master cylinder. You can try bleeding the master cylinder to see if that helps. Basically you want someone to get in, and push the brake pedal down ONCE to the floor and hold it. You then loosen one of the lines at the master cylinder, let the fluid pour out, and tighten it up. Then have them let up and push it down ONCE again and repeat. You'll wanna do this maybe 5-10 times for each line. If you still have the problem, it's probably a bad seal in the master cylinder.

[AceX]

Had the same problem. Have the rotors turned (machined). There's probably a hard spot on the rotors.

[benoit454]

Yea I had the drums resurfaced, and bled the lines again. the pedal doesn't go to the floor now, just goes down a little ways and catches, a bit more then a full pedal though, it's got about a 3/4 brake pedal, not completely full like if everything was new.

Well they told us the drums were kinda bad but he had him resurface them anyways. I figured they were BS'in cuz I know alot of ppl would rather sell you a 30-40 dollar drum per side then say resurface for 10-20 a side.

I have yet to try it out after the bearing, but if it keeps it up I'll end up getting drums, probably rotors, pads, and maybe calipers for a new brake system.

I did that on my monte carlo and it has great brakes after drums, rotors, calipers, pads and shoes.

[AceX]

That would make sense on the Monte because that's basically a new braking system...

[benoit454]

Yea it was definately worth it too. I'm going to try and do the same for the truck as soon as I have the extra cash.

It's a shame too because all them new parts and it sits and the rotors rust up lol I hate that. if it wasn't for needing the truck for hauling tools for work we'd just drive the monte and forget it for now. but we are right in the middle of a remodel job on a house for us to actually own and not rent lol. So we need the truck, plus it gets about 3 times the mileage my monte does.

Factory 305 compared to a pretty mild 350 lol.

[benoit454]

Yea right wheel bearing nut being loose seemed to fix it at first, but not long. After a short trip it was still doing it.

[benoit454]

Ok guys I'm stumped on this one. it still does it, I put on new tires and wheels so that eliminates any wheel bent, warped, out of balance, or tire belt broke or something.

Still does it.

It wants to pull to the right when you brake and wants to hop and shake/shimmy badly when on the brakes, it's the whole truck doing it, not felt through the wheel or brake pedal.

Now it's doing it without being on the brakes, but lightly, only feel the truck shaking or shimmying some what, then you hit the brakes and it intensifies it big time!!!!!

We checked all the front end for play and slop and found nothing.



So I'm left with theese options....


Idler arm? dad thinks it is.

Another steering componenet, ball joint, tie rod, center link etc.?

Front wheel bearings?

Rotor?

Or combination of the brakes in front maybe caliper or something?

Drums in back? They were turned but claimed to be bad, turned anyways.

ANY opinions on it?