Front brakes sticking somewhat after front end rebuild

[TheWarthog]

Hello all, new to the forum, hoping to tap into the wealth of knowledge from those of you on here. Im a younger kid but a few years back i really got interested in older cars especially the style of the 60's mopars. I bought a 67 Newport Custom 2 door a few years ago, steered like a boat but i used it as is for a while until a few years later when i was gonna have a shop reubuild the front end, till i got the estimate lol. Ended up doing it myself with the help of the manual and youtube, and taking tons of pictures to refer back to. New bushings where needed, new upper and lower control arm ball joints, new inner and outer tie rods and adjusting sleeves, new shocks, pitman arm, inner and outer wheel bearings and races, this that and the other, basically i just went off the repair shop estimate they gave me and replaced all the stuff they listed.

Obviously handling is night and day better now, but I am having a problem with the front brakes sticking somewhat. I can tell its holding the car back when its driven and when you get up past 20mph or so you can hear a high pitched whine. Sometimes at low speeds ill hear one of the brakes "chirp" as well like the pad has just suddenly got caugt on the rotor or something for a split second and the car will jerk to one side. When i get back from this very short drive, the front wheels are both hot afterwards.

Obviously since i knew something was off, i haven't driven it other then around the block here and there, just to not let the car sit for too long and whatnot. The brakes are disc brakes from an early 70's fury put on by the previous owner, rears are still drums, but what i can tell my issue is only with the fronts, the only ones i had to remove to work on the car.

Before i did the rebuild i had no brake issues. I've also bleed the brakes numerous times and its maybe only gotten a little better than it was originally, but car is still being held back.

I'm hoping you guys have some ideas for me. I know the car needs an alignment after a front end rebuild but was hoping to fix the brake issue before driving it to the shop for an alignment. Did the best i could with a home grown string method on youtube just to get them straight enough to drive around, but my question is, could it be the front end is so out of wack alignment-wise that is causing the brakes to rub? Or is my problem actually really with the brakes themselves. Also thought maybe when i did the new bearings i tightened the nut too much but everything was torqued to spec and i really dont think thats the culprit. Thank you for your assistance. The previous owner thinks i should get the rotors turned. Again nothing was wrong with the brakes until i had to take them off to start the front end rebuild, i took the brakes off when trying to troubleshoot the problem and worked the pistons with a spreader thinking they were stuck or something, not sure if thats it either, boots look good too, pads have plenty of life. Everything seems fine with the wheel rotation until i start bleeding the brakes and then it seems like they dont wanna let go from the rotor. I mean i know they should have some bite to them, but they are almost impossible to rotate by hand after bleeding them unless you really muscle it.

I read somewhere that maybe replacing the flexible brake hoses in the wheel well area is a possible fix. Again, hoping you all can help. Thank you.

 

[Big_John]

First thing that comes to my mind is if you damaged the front brake hose(s) when you took the front end apart. Any chance the calipers hung from the hose? The interior of the hose can break down and act like a one way valve. The fluid under pressure goes in, but doesn't back out.

 

[TheWarthog]

It's kinda hard to remember as its been a little while. I really dont think I let them hang while working on the car, i was pretty good about cradling the brakes in my hand while removing them. I did end up taking both brakes completely off and the flexible lines and setting them in the garage while working on the car. I was hoping to leave the brakes connected to the lines and suspend them with a bungee while i worked on the car, but since i had to take the flexible lines off to even get to one of the bolts to remove the brakes, leaving them connected was no longer an option if i was gonna get the brakes off.

The rebuild did take a while though, as i had to find time here and there to work on her. Maybe the hoses dried out and got messed up when finagaling it all back into place and putting everything back together? they did feel a bit stiff if i remember correctly. I am definitely unsure about the ages of the hoses themselves and maybe it would be a low hanging fruit to just get new ones and see what happens.

 

[Davea Lux]

You can start by replacing the front brake hoses to see if that helps. If this car were mine, I would rebuild the front calipers while I had it apart, that way you have eliminated another probable cause of the front brakes "sticking". The seals in the front calipers flatten out over time and this causes the caliper piston to stick and drag the brakes. If you had the calipers unhooked and off the car for an extended period of time, you might also have some rust inside the calipers caused by degraded brake fluid. Also check the front wheel bearing adjustment. Bearings that are set too loose will cause the rotor and caliper to wobble and do strange things to the brakes. Turn the front wheels by hand to see if there is any rough spots as the wheel is turning, could be an indicator of a failing bearing. Also check to be sure the caliper mounting pins are properly holding the disc brake pads in the proper place.

Dave

 

[thrashingcows]

What master cylinder and booster are on the car? Do you have a proportioning valve? As suggested I would replace the flex lines for sure, I've even had bad ones right out of the box!

 

[Rumble984]

did you check to make sure you didn't bend backing plate of rotor
maybe rubbing against rotor

 

[Barry S]

Can't add to what the experts have recommended, but I'd love to see some pics of your car!

 

[Ross Wooldridge]

Check the adjustment of the pushrod between the booster and the master. Too long and the master will apply the front brakes a bit all the time (kind of what you describe in part). Too short and the brakes might feel late and grabby...


However, that doesn't account for the chirp and pull situation you describe, but it does result in a feeling of "the brakes are on a bit all the time" you describe as well.

 

[67Monaco]

Bearing pre-load perhaps?

Maybe grease was on the rotor and contaminated the pads? Or maybe brake fluid on the pads?

When mine stuck it was because the bores were shot and the pistons stuck out. But that was on the BUDD four piston system.

 

[thrashingcows]

My first thought was as Ross suggested, but since he didn't say he removed the master cylinder I am leaning towards bad flex line. But the poorly adjusted bearing could cause issues, once they warm up and they become too tight they may give the feeling of brakes dragging.

 

[rkrochen]

These cars were prone to calipers rusting internally resulting in sticking pistons. The other area is where the caliper slides back and forth again these get rusty and don’t move well. I would replace the calipers and brake pads. Make sure you clean the retaining hardware and bracket, use a small amount antiseize on them so they don’t rust up again. Also inspect your hoses for cracks or damage, replace if necessary. Lastly you should get the rotors machined and repackaged the bearings.

 

[Wildaugust]

Check the adjustment of the pushrod between the booster and the master. Too long and the master will apply the front brakes a bit all the time (kind of what you describe in part). Too short and the brakes might feel late and grabby...


However, that doesn't account for the chirp and pull situation you describe, but it does result in a feeling of "the brakes are on a bit all the time" you describe as well.

You could try loosening (not removing) the lines at the master cylinder just to see if this releases the pressure and gets rid of the "on a bit all the time" feeling. If you're in a hot climate, I would suggest not driving it very much until you solve the sticking/dragging problem. I lost an automatic transmission on a hot day due to dragging brakes.

 

[TheWarthog]

Thank you all for your input, I did replace the inner and outer bearings and races during the front end rebuild. I was pretty good making sure the retaining nut was tightened to specs in the manual with an inch pound torque wrench and I went back and checked this several times as this was my first suspicion of what may be causing the dragging.

When i spin the wheels before putting the brakes on its smooth as a babys *** and I dont hear any noise or rubbing or any of that. Would also try to jiggle the wheels to see if there was any play such as if they were too lose, no jiggle. Also to answer Ross and trashingcows I never messed with the master cylinder. There is also a proportioning valve that was added by the previous owner when he did the disc brake upgrade.

Judging by all the input on here I will certainly replace the flex hoses, double check the backing plates arent warped, and see about either rebuilding the calipers or just getting new re-manufactured ones on rock auto or something, they arent that bad in terms of price. Having the rotors machined also is pretty cheap at the auto shop. The lines leading to the master are a little rusty so im afraid to crack them loose but i suppose I could give that a try too. God knows how old the master and booster are, I have no clue. Again everything worked fine before I removed the brakes to do the rebuild, she would stop great for such a gigantic car, now they are dragging regardless of if its when i first pull out of the driveway or whatever.

The caliper mounting pins were a b$#ch to get back in as one or 2 had a slight bend to it, maybe that could be the culprit as well. I guess I'll have to just knock out all this stuff listed above and see what happens. Will report back. Will also send some pics as Barry requested lol.

 

[thrashingcows]

Any wheel bearing needs to have a little bit of play in them for the expansion of the bearings when heated up, might spin smooth when cool in the garage, but once under load and the bearings expand they can tighten up pretty quick.

I was told many years ago to adjust the bearings so you can just feel a little in/out movement, but you can not see it move. Been doing it this way for decades now with no issues.

 

[TheWarthog]

It seems like the problem starts initially once i put everything back on and start bleeding the brakes. Like right after the first push of the break pedal (when doing the 2 man method) the brakes squeeze on the rotors and dont let go. It gets a little better once going around the car several times bleeding the brakes but it they never fully let go of the clampdown they have on the rotors no matter how many times i bleed them.

 

[Ross Wooldridge]

What you describe above sounds like the classic "failed brake hose" - where the inner portion of the hose restricts the return of fluid after the pedal is released, resulting in stuck on brakes. It can vary wildly even from application to application, as the inner failure is not static...

 

[TheWarthog]

Well thats going to be my first step then, replace the flexible hoses and if the problem persists, move on to the items others have mentioned on here. Again I thank everyone on here for their posts, will update on what happens.

 

[Big_John]

The caliper mounting pins were a b$#ch to get back in as one or 2 had a slight bend to it,

Ahhh.... I'm still going with the hose being the issue, but replace the bent pins as they could be contributing to the problem.

 

[TheWarthog]

Roger that

 

[TheWarthog]

Hey guys. I know this thread is from a long time ago but I finally did it!

Took the calipers off and swapped out the caliper pins and got new brake hoses. Lubed up the pins good and put it all back together. Bled the brakes and we are back in business. No more brakes clamping down on the rotors. I can tell its how it used roll now before I had this issue.

I may bleed the brakes one more time because I remember the brakes having a little more bite in regards to stopping power than it had when it was first driving good. Dont know if I lubed everything too good or if maybe I just need to bled the brakes a little more. All in all its not a drastic issue. I can still stop hard if I really press down. Maybe a little lube got on the calipers when I was puttin it back together. Thank you to all who had their input to offer on this. The batmobile is back.