New brakes too tight. Do I turn rotors?

So I bought a complete Power Stop brake kit for front and rear on my 70 GS. Came with drums, pads, hardware, front rotors, pads etc. Rears went together great.

The fronts I had to pretty much hammer on as the caliper was hitting the mounting bracket and are so tight the wheels barely spin. I rebuilt the calipers with new pistons and the pistons are all the way in. I did have all the suspension parts powder coated an maybe the thickness made the geometry slightly off. I really don't want to tear down the entire front end again and grind all the powder coating off.

I am thinking to just have the rotors turned but can't really find any auto places that still do this?

Anyone run into this or know who turns rotors in Western NY?

Thanks

 

Does the rotor free up if you loosen the caliper pins/bolts? And are you using drum brake spindles/knuckles?

 

I had similar problem with pads from powerstop on a camaro recently. But with my old rotors. I put sandpaper on a flat surface and sanded a little pad material off.

 

No they do not.

 

Thanks. That's probably easier that finding someone to turn the rotors.

 

Make sure the piston in the boisterous isn't too long...common issue with the kits out there today...there should be ZERO psi on the master when you bolt it up...if it's stock booster and master then the calipers are the culprit

 

Measure the rotor thickness and if correct, don't machine them. As hugger stated, the pistons are probably the culprit. Pop one back out and compare to the old piston. You can always sand the piston down if it's too long. If there is too much powder coating between the outer pad and caliper, sand it off. With today's Chinese parts, EVERYTHING has to be checked.

 

Just look at the puck is it flush with the caliper. If not, I would pull the puck and have someone put it on a lathe and cut it down.

 

What is the thickness of the lining itself ? Just put new pads on my truck and the lining itself was 15/32 . I was surprised it was that thick . Almost 1/2 an inch .

 

Any NAPA and most other parts stores still turn rotors and drums. I use Oreally's auto parts

 

The simplest solution that occurs to me is to simply remove the inner brake pad, and then test fit the caliper. This is to determine which pad is the issue.. If the outer clears with no issues, then just take the inner pad to a nice flat belt sander, and thin it out slightly to allow some clearance. or vice-versa... You could even do both pads if required.

Odds are, considering how most of are cars are used, you will never have to do a brake job on it again, so a slightly thinner pad is a non issue.

JW

 

I was referring to the pushrod in the booster....I've seen them too long more than once and will apply psi at all times.....no good obviously

 

I converted my Buick Special to disc brakes in 1991 and never had to replace the pads or any part of the front brakes until the car wore out due to rust in 2017. And I clocked a LOT of miles in that timeframe.

-Bob C.

 

I run into this quite a bit with disc brakes.
First you have rust crustys ( on a daily driver)
Clean that up/off, pad STILL doesn’t slide/fit into the bracket, ok grind a bit of the metal pad backing, ok it fits now!
I’ve come to the conclusion that the majority of “new” parts made for restoration or even your older daily driver are parts that are “pretty close” to the original part, they don’t fit like their supposed to.
Parts are sourced from ALL OVER and put in a manufacturers box.
I just did carrier and pinion bearings in my wife’s ‘08 Tahoe, carrier bearings were stamped “made in USA” pinion bearings were stamped “Koyo” same as original.
Carrier bearings were from BCA from Federated Auto Parts, axle and pinion seals were from China.
Pinion bearings were from O Reillys, those were Koyo, BUT they sold me two inner bearings (the larger of the two pinion bearings)
Most of the chain parts stores parts listing IS WRONG!

 

Nope not around here. No Napa's do anymore.

 

It's flush. And the same size as the originals.

 

Thanks all. Will take another look tonite. It appears the option will be to sand the pads. What grit paper would you use? And would you use an 80 and then a finer grit at the end? Thanks

 

Use 36 or 40 grit to surface or thin the pad as needed. Put the paper on a flat surface and turn the pad every few strokes to keep it reasonable flat. The roughness that is left will smooth out quickly, and the pad will bed nicely onto the rotor. Do not remove rotor material to make clearance.

 

Any guess at how “to thick” the pads are?
.010 .020? More? Less?

 

I just reread your original post. You state that the caliper is hitting the mounting bracket. This would have no bearing on the rotor not turning unless the coating was not applied evenly, allowing the caliper to cock. I think that either the powder coating is way too thick or something is bent. Is it only one side or both? If it's only one side, just swap the caliper temporarily and see if it goes on. You should be able to measure the rotor thickness and the distance between the pads when installed on the caliper. I think that you'll find that the powder coating is too thick, at least on the surfaces that ride on the caliper mount. There should be a spec listed in the service manual for the clearance between the caliper and the bracket. Also, make sure that the caliper bushings are free.