Wheel Cylinder pistons?

[Donald H.]

I have managed to get the correct 1 3/16" front wheel cylinders for my 1960 project car. They came from two different individuals, but they are the correct castings.

If you look at the photo note that the pistons are different. My questions is will that matter? I assume that it doesn't make any difference

[Joe L.]

Re: Wheel Cylinder pistons?

I have managed to get the correct 1 3/16" front wheel cylinders for my 1960 project car. They came from two different individuals, but they are the correct castings.

If you look at the photo note that the pistons are different. My questions is will that matter? I assume that it doesn't make any difference

Donald------


I don't think the piston configuration difference will cause any functional problem. However, I would not want to use any used pistons. I would obtain new ones if it is at all possible.

[Donald H.]

Re: Wheel Cylinder pistons?

Donald------


I don't think the piston configuration difference will cause any functional problem. However, I would not want to use any used pistons. I would obtain new ones if it is at all possible.

I would love to find new one if anyone has a source. I have found sources for the 1 1/8" bore cylinders, Corvette Central's 1 1/8" rebuild kit has new pistons but I have not found a source for the 1 3/16" piston!!

Don

[John F.]

Re: Wheel Cylinder pistons?

I just rebuilt all four of mine. Advance Auto still sells a generic rebuild kit. Cleaned up the old pistons with a light sandpaper and only used the spring and rubber cups from the rebuild kit. The dust caps were fine. Soaked the old parts in EvapoRust. Honed the cylinders. Now all back together.

[Joe L.]

Re: Wheel Cylinder pistons?

I would love to find new one if anyone has a source. I have found sources for the 1 1/8" bore cylinders, Corvette Central's 1 1/8" rebuild kit has new pistons but I have not found a source for the 1 3/16" piston!!

Don

Don-----


You're right. The last GM kit for the 1-3/16" wheel cylinders was discontinued in 1980 (which is 30 years ago now!).

I cannot find any source for the 1-3/16" cylinders or pistons. However, there just has to be one out there. Maybe some real specialty rebuilder or source from Hemmings.

Another option that might work: have the original cylinders sleeved for 1-1/8" bore and use more readily available 1-1/8" kits. I don't think you'd notice any difference in braking performance.

[Jim L.]

Re: Wheel Cylinder pistons?

Another option that might work: have the original cylinders sleeved for 1-1/8" bore and use more readily available 1-1/8" kits. I don't think you'd notice any difference in braking performance.

For 20 years I drove my '60 with 1-1/8 front wheel cylinders and never liked the way the pedal felt. Two years ago I installed some new 1-3/16 cylinders.

What I notice is that, while pedal travel is ever so slightly increased, the pedal effort is noticeably less. The brakes seem more eager to slow the car and I like the change.

The wheel cylinders I used were from a '69 or maybe '70 IH truck. Don, these could be an option for you. Buy a pair and either use them as-is or cannibalize them for their pistons. If you were to use them, the backing plates will require a minor modification that can not be seen once the drums are on. Let me know if you are interested and I'll look up the part numbers.

Jim

[Joe L.]

Re: Wheel Cylinder pistons?

For 20 years I drove my '60 with 1-1/8 front wheel cylinders and never liked the way the pedal felt. Two years ago I installed some new 1-3/16 cylinders.

What I notice is that, while pedal travel is ever so slightly increased, the pedal effort is noticeably less. The brakes seem more eager to slow the car and I like the change.

The wheel cylinders I used were from a '69 or maybe '70 IH truck. Don, these could be an option for you. Buy a pair and either use them as-is or cannibalize them for their pistons. If you were to use them, the backing plates will require a minor modification that can not be seen once the drums are on. Let me know if you are interested and I'll look up the part numbers.

Jim

Jim-----


It really surprises me that there is an appreciable difference between the 1-1/8" and 1-3/16" bore wheel cylinders. However, my experience with drum brakes pretty much ended a very long time ago.

I did find that Dorman Products offers a 1-3/16" bore wheel cylinder for 60's Corvettes under their number W 34151 and W34152. So, one should be able to buy a couple of these cylinders and transfer the guts to original wheel cylinders.

If it were me, I'd have the original wheel cylinders sleeved with brass or stainless and transfer the guts of the Dorman cylinders to the original, sleeved cylinders.

[Donald H.]

Re: Wheel Cylinder pistons?

I found a number of reasonably priced Centric 1 3/16" wheel cylinders on ebay for later model chevys and corvettes. I order one just to see if the pistons will work.

I am new to restorations and corvette ownership so I have no experience with brakes using 1 1/8" versus 1 3/16", but in an earlier thread where I was trying to identify what came on my project car, there were a number of responses that said there was a noticeable difference.

Thanks,

[Daniel K.]

Re: Wheel Cylinder pistons?

Contact the folks @ White Post Restorations. They can help with any slave or master cylinder.

I've used this service for all my cars.

http://www.whitepost.com/

[Jim L.]

Re: Wheel Cylinder pistons?

It really surprises me that there is an appreciable difference between the 1-1/8" and 1-3/16" bore wheel cylinders.

Joe,

The 1-3/16" cylinders have 11.4% greater area than the 1-1/8" cylinders. So, for equivalent pedal force, the force exerted by the wheel cylinder pistons will 11.4% greater.

Since Bendix brakes are self-energizing, I have a hunch that the actual braking force of shoe against drum will be more than 11.4% greater with the larger wheel cylinders.

It's 40 years since I was forced in engineering school to wade through the calculations for self energizing brakes, but I think my hunch is pretty accurate. In any event, with the long term familiarity I have with my '60, I immediately noticed the difference in brake pedal feel when I went back to the 1-3/16 wheel cylinders.

Jim

[Jerry K.]

Re: Wheel Cylinder pistons?

I found a complete wheel cylinder for a 64 chevy passenger car at a local parts store and used the 1-3/8" pistons from them. I had Apple Hydraulics sleave them in brass for about $200.00, more for a complete rebuild. I swictched to synthetic brake fluid and am very satisfied with stopping and tracking of my 62.