Dual Pin brakes on rear

[Mike Cobine]

Several days ago, someone was asking about the dual pin J56 calipers on the rear. Here is a shot of the ones on the James Garner A.I.R. Corvettes. Now these had been made in the shop and one thing curious is the use of the angled front style backing plate pad on the outside and the standard style pad on the inside.

If you look closer, check the u-joint strap on the rear end. A bit strange for an L88.

[Mike Cobine]

Should have attached the picture

Here is the picture so you dont' have to go look.

[Mike Cobine]

Another curiousity

Here is a place not really here anymore, but the item that is curious is the crew cab car hauler.

[Curtis L.]

great pics *NM*

[Joe L.]

Re: Dual Pin brakes on rear

Mike-----

My interpretation of the question that you referred to was that it involved whether or not dual pin calipers were ever ORIGINALLY installed on the rear calipers of J-56-equipped cars. The answer to that question is simple and straight-forward: dual pin calipers were never ORIGINALLY installed in PRODUCTION on the rear calipers of any 1965-75 Corvette equipped with J-56 brakes.

As far as what could be done in terms of modification, as always, the sky is the limit.

[Mike Cobine]

Re: Dual Pin brakes on rear

Joe, if you look at the picture closely, it looks like they run the brake line in on the top inside and have a bleeder on the bottom outside. Clearly not original. Angled dual pin front pad on the outside and a regular style on the inside. U-bolt strap retainers on the u-joint instead of the bolt and cap. There is a lot of this that is not original.

Odd thing is the frame is not fully welded, a standard prep on a race car of this level.

[Joe L.]

Re: Dual Pin brakes on rear

Mike-----

Yes, in this case, there are many other aspects of non-originality with respect to what can be seen. Notwithstanding this, it would be very possible for someone to convert the rear brakes of a J-56-equipped car to dual pin and add the J-56 front brake pads to the rear without making any other modifications, at all. Such an installation might "appear" as being original. However, it would not be.

[bruce11495]

Re: Another curiousity

Mike....Would this picture have been taken in the Holiday Inn parking lot across from Daytona? Graet pictures.............

[Dick W.]

Re: Another curiousity

Apparently after practice or a race. Look at the Porsche on the trailer. Slight misalignment of rear suspension. Michael will have to chime in on the location but I sort of agree with you. I remember seeing the hauler somewhere and Daytona or Riverside would have had to been the location. And Riverside did not have the motels on site.

[Mike Cobine]

The James Garner A.I.R. Corvettes

The James Garner American International Racing 1968 Corvettes have a good assortment of pages. This is the Holiday Inn across from the Speedway entrance. We were over at the Speedway in January and it is amazing how different it is today. The Holiday Inn is something else, and doesn't look like this. The gas station was drastically different. A friend working at the Speedway this reported there were 300,000 in attendance, a far cry from what would fit years ago. Look at the front grandstands in the picture. Today, the back straight grandstands are about triple that size.

If you haven't been to this site, bookmark it and spend some time.

http://www.airl88.com/

[Mike Cobine]

Re: Dual Pin brakes on rear

Actually, Joe, it was very common for any car raced to have the rear caliper cut down to use the front pads. Now some probably used them stock, just as I have seen some use the stock production regular brake calipers on race cars (and they probably wondered why they couldn't stop).

In late '87, I went to get pads from Chevrolet and all they had were the front pads available. They were $400 an axle set, front only. They didn't have any rear in the HD version. Do you have any info on the HD rear pads? Liek how long did they have them, when did they quit, etc.?

[Mike Cobine]

[Dick W.]

Re: Dual Pin brakes on rear

Sure brings back a lot of memories. Having a serious nostalgia attack. I was there as a spectator. We were looking to build a Camaro for the new NASCAR Grand American Series

[Joe L.]

Re: Dual Pin brakes on rear

Mike-----

I don't doubt that it was common on raced cars. All sorts of modifications are common on raced cars. However, the cars were never originally built that way.

As far as the brake pads go, the original 65-66 J-56 front pads were GM #5452514. I believe that these pads used a steel backing plate and may have been riveted rather than being bonded, but I'm not sure about this. For 1967 and 1968 that changed to GM #5463160 and, in July, 1967, these became the SERVICE pads for 65-66 when the 5452514 were discontinued. I don't know anything about the 5463160 pads. I believe that they were bonded, though, and of non-metallic pad compound.

For 1969-75 the J-56 front pads became GM #5468882. These pads are a non-metallic, HD compound which is bonded to the backing plates. The backing plates for these pads were made of Inconel and these were manufactured for Delco by Raybestos. The 5468882 became the SERVICE pads for 65-68 J-56 fronts when the 5463160 were discontinued in December, 1968.

The GM #5468882 were finally dicontinued from SERVICE in April, 1987.

The rear pads for J-56 installations were GM #5452514 from the very beginning of J-56 installlations right through to the last in 1975. These are a non-metallic HD pad compound that are bonded to steel backing plates of the same configuration as standard brakes. They were dicontinued from SERVICE in July, 1984.

[Mike Cobine]

Dual Pin brakes on rear - not factory

Thanks, Joe, for the input on the pads. I guess it is a good thing I didn't order a set in '87 as the dealer probably didn't know they were discontinued, and he would have kept me on a backorder list for months.

The old set I have I'll have to check as to being metallic or not. I think they may be the 5468882 pads as the backing plate looks almost like a stainless steel but slightly discolored.

It is not surprising that they were discontinued then as after SCCA changed the big Production classes into GT and allowed any brake setup, the racers ran away from the J-56 to the Wilwood and other calipers rapidly. Ferrodo made organic pads that stopped much better than the J-56 with less tendency to wear at an angle. They ran $90 an axle set, compared to the $390 from Chevy.

However, the cars were never originally built that way.


Joe, you keep harping on this, but I have never once implied that they were from the factory. Each time was in reference to a race car. Each time I said the tops were cut and holes drilled to use the front pads in the rear. The original poster asked about them on the back, and I said if you are looking at an old race car, then this was a very common practice to do for serious racing.

I didn't say, but he could imply, that if dual pin brakes are found on an old car, the car probably had a serious racing period, or someone pulled them off a real race car to make a fake J-56 car.

The fact that this modification is not mentioned in the Chevy Power Manual means they a) were ignorant of the wide-spread practice (doubtful), b) felt that the factory configuration was satisfactory (probable), c) chose to ignore the braking so they could not be held responsible if someone messed it up, or d) didn't have a clue how to improve them.