rustyShake

Ok so this has been an ongoing issue which I've ignored for a while. This is the original post:
https://www.yotatech.com/forums/f123...ts-end-296396/

But after a year of driving I believe my front brakes are still dragging. While I was rotating my tires yesterday I realized the front driver's side wheel, in particular, is dragging excessively. I cannot spin the wheel with one hand, and when using two hands, as soon as I stop applying force, the wheel stops immediately. Last year I tried chasing down this problem to no avail. I replaced both brake calipers, brake pads, new front brake hoses, even replaced the master cylinder.

I'm positive this is a brake issue because when I remove the caliper, the hub spins freely. Last year I gave up thinking I was just chasing a ghost and that it must have just been the way it's supposed to be. However, it seems my driver's side has gotten worse, and the passenger side is still not good. It is heating my rims (nothing is glowing red hot, but they get hot) and the center plastic lug cover is turning gray from the heat (pretty sure that's why the paint is peeling off).

Anyone have any advice? Has anyone else with a RWD 1st Gen Taco tried jacking up their front end to see how freely the front wheels spin? Am I crazy here?

Thanks,
Erich

tags: front, brakes, brake, stick, sticking, drag, dragging

akwheeler

When you replaced the master cylinder did you check pushrod adjustment?

rustyShake

Kind of. I wasn't sure how to check that/measure that exactly, so I did a jimmy-rig version. I backed off the bolts holding on the Master Cylinder until there about 1/4 to 1/2 inch of gap between the MC and the Brake Booster (I put a wedge to keep the gap and make sure everything was still tight). I then checked the wheels to see if the situation had improved, and it didn't. My thinking was that with the additional gap b/w MC and BB, that should ensure the pushrod is being allowed to fully extend and I could then rule it out as the issue.

**EDIT: also, the dragging problem existed before I changed the MC. I changed the MC b/c I thought it was causing the drag issue.**

akwheeler

Do you mean you put a gap between the brake booster and the firewall? You should also do this between the master cylinder and the brake booster. just loosening the nuts should be enough to tell if there is a difference.

wyoming9

iTrader: (1)

Ok Are your pads dragging to the point the rotors and calipers start to turn a dull red color ??

Your driving in Low Range because it won`t move otherwise??

Every time you drive as much as 50' the sweet smell of hot brake material follows where ever you go.

Melrose 4r

THIS. it is a very common problem on muscle car front brake swap kits and i experienced it on my own 67 Camaro.
jack the front wheels off the ground. Unbolt the master from the booster and separate them a bit. See if the brakes stop dragging.
if so shim out the master with appropriate width washers or shorten the internal pushrod. Not sure if there is an adjustment, you might have to grind it down but use the washer trick to determine where it feels right and doesnt drag. In my case about .030" made all the difference.

rustyShake

Yes, sorry. I mean I loosened the MC from the Brake Booster, not the firewall. I misspoke. I did not improve the situation with the brakes.

rustyShake

I did exactly that several months ago. It did not help. I loosened the bolts from the MC and separated it slightly from the Brake Booster. It did not help.

rustyShake

I will also say that my brake fluid got nasty looking fairly quickly. It is pretty dark now. When I did all this brake work several months ago, I bled the entire system.
Also, my calipers look a little blue. Not sure if that's from excessive heat or if that's a normal wear pattern.
Repeat, I do not notice any glowing red around the calipers when/immediately after driving. The wheels are hot though!

akwheeler

jack up the front end, see how hard it is to rotate the front tires, crack a bleeder loose and see if it gest easier to spin. If so you have something retaining pressure to the caliper/s. then pump your brakes and see if it gets hard to spin again. move up to where the brake hose connects to the hard line and crack it there. if the wheel is still hard to spin you need to replace the brake hose, if not you need to keep moving up the line like right at the master cylinder to find where there may be a blockage retaining pressure if cracking the line at the master cylinder releases the brakes try pumping up pressure, duplicate the drag, and without disconnecting lines completely unbolt it from the booster. If none of this helps or steers you in the right direction post your results.

Terrys87

iTrader: (1)

I flush my brake lines with an air hose starting at the caliper/drum to the master cylinder and reverse the procedure. Then I fill the lines with Marvel Mystery Oil and flush the lines again. You will get a lot of rust out of the lines doing it this way.

i too have experienced dragging front brakes. Never had an issue with the rear brakes dragging. What my problem was, it was the brake booster. The way I found out my booster was bad was I disconnected the air line to the booster and plugged the line off with a bolt. Doing this you will have less then 25% braking power. You can stand on your brakes as hard as you want and you will not lock up the tires.

I would drive around a safe area with the hose disconnected and plugged and see if your brakes are still dragging with the booster out of the system. Somehow with a bad booster will let the vacuum circle around and apply the brakes in the booster without you touching the brake pedal. Do the above test in a very safe area as you will have very little braking.

When my booster was bad, it took about 10 miles for the brakes to start getting hot from dragging.

RAD4Runner

Picture below is an anti-rattle spring. It actually pushes the brake pads away from the rotor. There is only one per side. The brake pads are symmetrical and have holes where a second anti-rattle spring can be installed.
What if we got an extra set from the junkyard and installed it? That might help push the pads harder AWAY from the rotor.

akwheeler

Those anti-rattle springs don't have enough tension to push the caliper pistons back. You could put a dozen on there and it would have little to no effect, but you sure wouldn't get any rattle from the pads! What pulls the pistons back it the elasticity of the square cut seals in the caliper, if they get hot they loose their flexability. if the rattle springs did the work they would push the pads back too far from the rotor and you would constantly have too much pedal travel before you got any braking.

akwheeler

there is no more definitive test than what I posted earlier "jack up the front end, see how hard it is to rotate the front tires, crack a bleeder loose and see if it gest easier to spin. If so you have something retaining pressure to the caliper/s. then pump your brakes and see if it gets hard to spin again. move up to where the brake hose connects to the hard line and crack it there. if the wheel is still hard to spin you need to replace the brake hose, if not you need to keep moving up the line like right at the master cylinder to find where there may be a blockage retaining pressure if cracking the line at the master cylinder releases the brakes try pumping up pressure, duplicate the drag, and without disconnecting lines completely unbolt it from the booster. If none of this helps or steers you in the right direction post your results. "
I would wait to hear back from rusty on the results, if there is retained pressure in the brake lines when the pedal is released nothing will stop the brakes from dragging.

Melrose 4r

What kind of pads and rotors? Are they OEM? If not what is the pad and roto thickness compared to the new thickness of OEM?
Are the pads wearing evenly? If not there could be a clue in that.
Are the wheel bearings good?

RAD4Runner

No, not push the pistons back. Just the pads so they're not pressing on rotors as much.
But thanks for the tips on checking for clogged lines.

akwheeler

If the pads are touching the rotor with enough force to cause a noticeable brake drag an extra anti rattle spring won't help.

Thommo Thompson

can i just introduce myself here as somewhat an expert in this issue.
this issue is often a result of two things.
1.sticking slide pins from old worn or remanufactured pads (relined) and
2.air in the brake lines.
the details behind each are as follows.
1. if a wheel bearing is slightly worn amd allows the disc runout to exceed specs, this will put uneven pressure on the pads when cornering and braking at the same time. This unever pressure causes the outside of the disc to heat up more than the inside causing a conical warping tendancy. this tendancy is hampered by the sheer strength of the disc and the result is that the disc warps like a broad brimmed hat. This means that 2 opposite sides of the disc are at different runouts than the perpendicluar opposite. this causes the centreline of the brake to move in and out visciously which wears out the slide pins even further as the pads move in and out. Machinesng the discis will help, but if your seeing brake pads visually moving in and out and contacting the disc so much that its sticking then new discs are in order. All of this is initially caused by the wheel bearing. so after u resolve this, that will have to be looked at.

2. when DIYers like myself, look after their own brakea, often the two man bleed or one man one way bottle and pumping method is used.
these techniques are hopeless. when the air doea get in, the user ends up tightening all the wrong parts in an effort to fix the sponginess, and in doing so, disables the master cylinders ability to back off behind the oil inlet to equalize the system when the brake is released. this causes the aystem to be in a half assed aired out but over tight scenario. If u back off the adjustment it spins freely but then ur brakes are spongy so u go and tighten it. This ia chasing your tail. the reason it stays night n tight is u are no allowing the brake fluid to be released back into the reservoir, and thia stops the air bubblea from expanding and making it spongy and u get the wrong idea uve resolved the sponginess.
u muat use a vacuum brake bleeder when this situation arises, and then ensure there ia no modification to the brake booater to master cylinder pushrod and that at rest, it allows the master cylinder to completely return to fully back.

akwheeler

And humble too I see!

Melrose 4r

Some parts are mismatched if nothing else solves this. Take some ACTUAL DATA by measuring pad thickness and rotor thickness with a cheap digital caliper and then you'll be able to tell us what you are working with.