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-   -   Need Advice: Which Brake Setup to Buy (http://www.hotrodders.com/forum/need-advice-brake-setup-buy-68915.html)

horvath 08-26-2005 03:39 PM

Need Advice: Which Brake Setup to Buy
 
I need some advice from y'all in the know:

I've got a Mustang II IFS on my 54 Chevy pickup, with 1982 Monte Carlo 11-inch front disc brakes. I went to put new brake pads on today and attempted to put new rotors, too, but came up with a problem ... the new rotors ('82-'88 Monte Carlo) were fatter than the calipers! The brake pads on the inside were okay, but on the outside, the pads were about 1/8-inch into the rotor! So I couldn't install the new rotors.

I don't get it.

Anyway, we just put the new pads on (with the old rotors) for now and left it at that. Now my braking is spongier than before, but it's okay. I'm thinking I'll buy a new rotor and brake kit from JEG'S or something and just replace the whole setup ... I'd like to do this ASAP.

Something isn't right with my present setup ... the left-front brake pad was worn in a wedge shape, like 1/4-inch more worn in the front of the pad than the back.

So ... can anyone direct me to the "best" setup to buy? How do I determine what to get -- is what I want to order just based on the Mustang II front end?

Thanks for your help.

Alan
54 Chevy Pickup

66GMC 08-26-2005 04:46 PM

Hi Alan,
Uneven wear on brake pads is usually a sign of sticking caliper slides.

Disc brakes are designed so that the piston applies the force from one side of the caliper, but the caliper slides on the steering knuckle so that it centers itself on the rotor in order to apply an equalized clamping force to both sides of the rotor. (I hope that I'm explaining this well enough.)

As the friction material wears, the piston extends further and further out of it's housing in the caliper. When you install new pads, you have to push the piston back in it's bore until the new pads clear the rotor. The way that I do that is to loosen the bleeder screw, and compress the piston back into the caliper using a C-clamp.

So inspect, clean, and lube the caliper pins, bushings, and sliding surface on the steering knuckle. Use a silicone-based "disc brake caliper lube" like Permatex #31877 (which is a 5 gram "counterman's choice" retail pouch containing enough lube for a single application.)

HTH,
Don

horvath 08-26-2005 06:04 PM

Quote:

Originally Posted by 66GMC
When you install new pads, you have to push the piston back in it's bore until the new pads clear the rotor. The way that I do that is to loosen the bleeder screw, and compress the piston back into the caliper using a C-clamp.

Thanks, Don

We did that, but the new rotors are too thick and the outboard pads won't clear the rotor - by 1/8th-inch ... the only solution I can think of is to shave the brake pad down and I'm hoping for a better solution than that.

I called JEG'S and talked to a tech there and he said a lot of times new rotors, being made overseas, are milled too thick and this is becoming a common problem!

What to do?

The new pads fit okay on my old rotors, but now my pedal is spungy (mushy) and I'd hate to see what would happen if I had to stop short!

Alan
54 Chevy Pickup

66GMC 08-26-2005 10:00 PM

Quote:

Originally Posted by horvath
Thanks, Don

We did that, but the new rotors are too thick and the outboard pads won't clear the rotor - by 1/8th-inch ... the only solution I can think of is to shave the brake pad down and I'm hoping for a better solution than that.

I called JEG'S and talked to a tech there and he said a lot of times new rotors, being made overseas, are milled too thick and this is becoming a common problem!

What to do?

The new pads fit okay on my old rotors, but now my pedal is spungy (mushy) and I'd hate to see what would happen if I had to stop short!

Alan
54 Chevy Pickup

Hmmm... puzzling indeed.

I work at a NAPA store here in Canada where we sell 3 "grades" of brake rotors and several different "grades" of friction material as well. (NAPA has really gotten on the "Good, Better, Best" kick in recent years ... likely due to a lot of competitively priced off-shore crap!

Rotors:
"NAPA United","TRU-STOP", and now a new line called "Brake Right".

Friction:
"NAPA United" (AE = Application Engineered, SS = Safety Stop,CMX = Ceramix, SD = Severe Duty), "TRU-STOP", and possibly "BrakeRight" as well.

When they first introduced these lines we jokingly referered to them as "SureStop", "ShouldStop", and "MightStop" :D

We stock the "Best" and "Better" lines, and draw the line there.

The "TRU-STOP" line of rotors is a "white box" sort of line intended for the "value-conscious consumer". Most of it is not too bad ... in fact some of it is mfr'd by ITT/Aimco and made in Canada ... very good quality, while others are made in China and packaged in "rice cardboard". My installers say that they have to occasionally put brand new stuff on the brake lathe to "true it up" and then re-install on the car in order to get it out the door. I do understand that this can occur due to improper storage ... rotors need to be stored flat, not on edge, and not in tall piles either.

With this in mind, you'll understand why we drew the line there. We (in our independently-owned associate store) DON'T WANT to attract the type of clientele that would buy anything less. They're the type that will think nothing of spending $20.00 for a dozen beer and $10.00 more for a pack of cigarettes, but whine like hell over spending more than that $30.00 on brake parts! I just don't get it.

Anyway! ... on to the point:
I have not yet heard of any of these off-shore rotors being too thick. I think it's more likely that you have simply been sold the wrong parts ... trust me ... parts people are human, and do make mistakes. :eek: One of the most common mistakes are "dyslexic" number reversals (i.e. 88630 instead of 88603)

1.) Check to make sure that the part numbers on your invoice matches the part numbers on the boxes.
2.) Have your supplier check the application again and carefully compare the part numbers to what you have already bought.
3.) Ask if there might be any other optional listings that may have been dismissed. ("Most times it's this one" scenario.)
4.) Insist on buying the "name-brand" parts ... or at least get him/her to bring both types to the counter for comparison. Check them with the naked eye, and then check them with a digital caliper.

Finally, if your brakes have become "spongy" since you had them apart, it is quite likely due to the fact that air has been introduced into the brake system somewhere, perhaps at the bleeder screws or at the master cylinder.

I'll assume that you did use the correct (likely DOT3) and fresh brake fluid while topping up as well?

I'd be more than willing to try to cross-reference the part numbers that you have, and see if I come up with anything different for your application.

HTH,
Don

66GMC 08-26-2005 10:07 PM

"Short - Lines"
 
Oh yeah ... one more thing to mention.

Some of those value lines are what we call "short lines"...
where only the fastest-moving part numbers are available. The lower-volume (sometimes "optional" or odd-ball) part numbers may ONLY be available in the premium line.

Don

horvath 08-27-2005 07:41 AM

Thanks, Don

That's good info and I'm gonna pass it along to my mechanic next week -- I want to get this resolved!

Alan
54 Chevy Pickup


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