Front Brake Issue/Question

[James T]

Good day,

I'm experiencing some front brake symptoms and would appreciate any information about dealing with the Avanti's Bendix version of Dunlop disk brake technology circa 1953.

When I apply the brakes, I feel a slight pulsing in the braking action. It's a bit like what I've felt before with warped rotors, but it's more aural than physical. I can hear it more than feel it. When I release the brake pedal it's as though the pads are not fully retracting and I can hear them rubbing/squeaking.

I've read Bob Johnstone's tips and it sounds like this is the classic case of the pads wearing unevenly. So, I plan to replace those immediately and I'll be inspecting everything carefully in the process. I have a shop manual and am aware of the procedure, but is there anything specifically that I should be looking for or replacing in addition to the pads?

I would prefer the Turner brake upgrade, but I'm not willing to give up my Borranis in the process.

[Gunslinger]

I would contact Jon Myers at Myers Studebaker. He's as knowledgeable as anyone I know of for any issue on these cars. I recently had a brake problem on my car (different issue than yours) and asked Jon...as soon as I told him what was happening he knew what he problem was though long experience and I was able to get the brake issues corrected quickly.

Jon's business number is 740-674-4897.

[WayneC]

Could be just dirt around the pads, keeping one against the rotor after the pedal is released,

...or one pad so worn that the piston is sticking in the out position.

1. Check the rotor faces for radial rust streaks from rainwater if the car hasn't been driven a lot recently;

since you aren't experiencing a pull to one side, this may be the most likely cause.

If not, and changing the pads doesn't cure it...

2. With car jacked up and wheel removed, grip opposite sides of the rotor and wiggle it to

check for looseness (bad/loose wheel bearings); do that again at other clock positions;

also make sure the rotor spins freely without binding.

3. Check to see that the rotor is centered in the caliper (use feeler gauges between the

caliper and the rotor front & rear, on both sides)... if the measurements are not all really close,

there are shims available for the caliper mounting bolts to correct the positioning.

4. When a brake booster goes bad, it can cause the brake pads to stay snugged against the rotor

(generally you'll also notice there's less than the normal brake pedal movement before the brakes firm)

5. Measure the thickness of the rotors where the pads contact it; I believe the minimum thickness

is 0.3 inches (don't have my shop manual handy, you'll find the minimum dimension there)

6. Check for a warped rotor by attaching a dial indicator to the caliper and measuring runout as

the rotor is rotated; again, the minimum allowed run-out is in the shop manual.

7. A very slight brake fluid leak conceivably could cause pad "skipping" on the rotor surface (not likely).

Good luck.

[James T]

Following the shop manual and Wayne's advice, I dove into the brakes this weekend and here's what I found out FWIW -

First, there was a buildup of grease/dirt/gunk between the rotor and the dust shield. The previous owner had been rather generous when lubricating the front end, so I hope it was just some overflow that started this. I cleaned everything with spray brake cleaner paying special attention to the rotors.

Secondly, the calipers were not centered on the rotors. No telling how long this had existed, but I did at least find the spacers were still there. After several trial-and-error attempts, I got them within the .02" difference spec.

Third, the pads were defintely worn down, maybe 30% of the surface left compared to new ones. I obtained replacements from Advance Auto. They cross-referenced the part number to an early Datsun model that used the same Dunlop disks. And, well, they almost fit. They were just a smidgeon too wide, so I put on my Darth Vader respirator and ground off the edges enough to make them fit. They were identical otherwise, and retailed for $26 and no shipping cost.

The good news is that I now have excellent stopping power and the pulsing/grinding noise is gone.

The bad news is that I now have a depths-of-hell-banshee squeal from the new pads. I have bedded them in using the method of several low speed stops consecutively, and then some moderately high speed stops. They don't squeal at all in very light or very heavy applications, only in that middle area where you do 90% of your braking! Is there any value in anti-squeal stuff on the pads? Can I expect this to improve with use or do I need to think of turning the rotors now? They are original, 58K miles, and did not exhibit undue runout.

Oh, I did contact both Turner and Steeltech about their brake upgrade kits. Both seem to think their kits would work fine with my Borrani wire wheels. If all else fails, this would be my next move. Both use the Ford rotors and GM calipers, but Steeltech is about $100 cheaper. Anyone have experiences/comments about either?

[ernier]

The squeal could be the result of new pads on rotors that weren't resurfaced. It may go away. I used the Turner brakes. The availability of GM pads and the throngs that praise Jim Turner's service led me to his product. Steeltech has a reputation for long delivery and less than prompt response to questions. I can only say that the Turner brakes work great and would highly recommend the swap. I recouped most of my upgrade expense by selling the Stude stuff on ebay.

My only quibble is the lack of splash guards with either Turner or Steeltech. I plan to fabricate something, one of these days(G)

Ernie 64 R2 R5388

Following the shop manual and Wayne's advice, I dove into the brakes this weekend and here's what I found out FWIW -

First, there was a buildup of grease/dirt/gunk between the rotor and the dust shield. The previous owner had been rather generous when lubricating the front end, so I hope it was just some overflow that started this. I cleaned everything with spray brake cleaner paying special attention to the rotors.

Secondly, the calipers were not centered on the rotors. No telling how long this had existed, but I did at least find the spacers were still there. After several trial-and-error attempts, I got them within the .02" difference spec.

Third, the pads were defintely worn down, maybe 30% of the surface left compared to new ones. I obtained replacements from Advance Auto. They cross-referenced the part number to an early Datsun model that used the same Dunlop disks. And, well, they almost fit. They were just a smidgeon too wide, so I put on my Darth Vader respirator and ground off the edges enough to make them fit. They were identical otherwise, and retailed for $26 and no shipping cost.

The good news is that I now have excellent stopping power and the pulsing/grinding noise is gone.

The bad news is that I now have a depths-of-hell-banshee squeal from the new pads. I have bedded them in using the method of several low speed stops consecutively, and then some moderately high speed stops. They don't squeal at all in very light or very heavy applications, only in that middle area where you do 90% of your braking! Is there any value in anti-squeal stuff on the pads? Can I expect this to improve with use or do I need to think of turning the rotors now? They are original, 58K miles, and did not exhibit undue runout.

Oh, I did contact both Turner and Steeltech about their brake upgrade kits. Both seem to think their kits would work fine with my Borrani wire wheels. If all else fails, this would be my next move. Both use the Ford rotors and GM calipers, but Steeltech is about $100 cheaper. Anyone have experiences/comments about either?

[WayneC]

The bad news is that I now have a depths-of-hell-banshee squeal from the new pads. I have bedded them in using the method of several low speed stops consecutively, and then some moderately high speed stops. They don't squeal at all in very light or very heavy applications, only in that middle area where you do 90% of your braking! Is there any value in anti-squeal stuff on the pads? Can I expect this to improve with use or do I need to think of turning the rotors now? They are original, 58K miles, and did not exhibit undue runout.

I've had lousy luck buying pads at the local parts stores over the years, sounds like you did, too.

As I found out, saving a few bucks on pads is false economy.

Order a set of pads from Nostalgic Motors: 1-800-avanti1 ($40 + shipping)

If the rotors are excessively shiny or have a lot of grooves or pits, then take the time to remove them

and have them turned (I always implore the shop to take only a minimal cut to smooth the rotor face, to

prolong the life of the rotors, which cost about $250 each).

[James T]

Thought I should add a final note on this topic, having started it.

I bought and installed the brake kit from Turner. As others had said, this is a very well engineered and constructed kit with all parts needed for $650. During the installation I discovered a leaking grease seal on one wheel bearing which was the source of my original problem.

No matter, the end result is much improved and gloriously silent braking, easier future maintenance, and a happy owner.

Anyone need any stock Avanti brake parts? ;-)

[Gunslinger]

Anyone need any stock Avanti brake parts? ;-)

That's what Ebay is for!

Glad to hear you're happy with your new brake system. I considered either the Turner or Steeltech system for my car, but decided against it both Turner and Steeltech each said their systems wouldn't be compatible with Magnum 500 wheels. I've seen some Avanti owners have said they had no problem, but like some things with Avanti's, that seems to be a car by car thing. After already buying new tires for the Magnum 500's, I couldn't see the further expense of new wheels and new tires all over again. Besides, the stock brake system is operating fine and seems to do the job well.

[ernier]

I cleaned and packaged all my pieces and sold them on ebay. My calipers were stainless sleeved so I may have gotten a little better price but if I remember correctly the auction ended up close to $300.

BTW, I have had very good performance from Hawk brake pads. One of my sons was doing CAD work for a performance brake company and turned me on to them. I have them on 3 cars including the Turner equipped Avanti.

Ernie R2 R5388

Thought I should add a final note on this topic, having started it.

I bought and installed the brake kit from Turner. As others had said, this is a very well engineered and constructed kit with all parts needed for $650. During the installation I discovered a leaking grease seal on one wheel bearing which was the source of my original problem.

No matter, the end result is much improved and gloriously silent braking, easier future maintenance, and a happy owner.

Anyone need any stock Avanti brake parts? ;-)