1963 - 1965 Front Wheel Cylinders

[Harry S.]

Re: 1963 - 1965 Front Wheel Cylinders

Guess I had a brain fart. What I installed last summer was two rebuilt Delco wheel cylinders. They were both leaking in the same spot. Both were leaking/weeping at the copper washer. I cleaned the area, installed new copper washers and new rubber on both sides. I'll add brake fluid, DOT 4, and look at it in the morning. If all is dry, I'll bleed them.

Has anyone see this before. The old rubber lines came from LIC last summer.

Well, they were not dry. The rebuilt Delco wheel cylinders with the new copper crush washers and rubber lines were still leaking at the crush washer. This week I removed them and installed new NAPA wheel cylinders, with new crush washers and the same rubber lines. No leaks. I bled the brakes today and all is fine. High hard pedal.

What am I missing? The rubber lines do not bottom out in the cylinder. The crush washer should be fine. Was there a special crush washer made for those original wheel cylinder?

Just confused on this one!

[Joe M.]

Re: 1963 - 1965 Front Wheel Cylinders

Give Apple Hydraulics in NY, a call. Used them over the years, never had a problem.

[Harry S.]

Re: 1963 - 1965 Front Wheel Cylinders

What is the sealing point at the wheel cylinder from the brake line? Is it the brake line bottoming out inside the wheel cylinder or is it the crush washer, or is a combination of both?

Thanks

[James W.]

Re: 1963 - 1965 Front Wheel Cylinders

Harry,

I would think that the flared fitting on the brake line should seal against the beveled/flared surface in the wheel cylinder.

James

What is the sealing point at the wheel cylinder from the brake line? Is it the brake line bottoming out inside the wheel cylinder or is it the crush washer, or is a combination of both?

Thanks

[Harry S.]

Re: 1963 - 1965 Front Wheel Cylinders

Harry,

I would think that the flared fitting on the brake line should seal against the beveled/flared surface in the wheel cylinder.

James

James, I thought that also, but the threads on the rubber line would need to be 1/4 inch longer in order to bottom out.

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[Dan B.]

Re: 1963 - 1965 Front Wheel Cylinders

Harry, I think the issue with those wheel cylinders is the rings (grooves) shown where the crush washer seats. That is the sealing point, you would have to really crank down on the hose fitting to get the washers to deform to seal. It's hard to see if there may be some surface irregularities on yours. I light dressing with a flat file could help smooth out any bad areas. I checked some older US made Wagners I have and that surface is machined totally flat on all. I no longer have any Delco 63-64 front ones I can check to compare with yours, those got sold.

[Harry S.]

Re: 1963 - 1965 Front Wheel Cylinders

Harry, I think the issue with those wheel cylinders is the rings (grooves) shown where the crush washer seats. That is the sealing point, you would have to really crank down on the hose fitting to get the washers to deform to seal. It's hard to see if there may be some surface irregularities on yours. I light dressing with a flat file could help smooth out any bad areas. I checked some older US made Wagners I have and that surface is machined totally flat on all. I no longer have any Delco 63-64 front ones I can check to compare with yours, those got sold.

Dan, I looked at that. I compared the two, to another Delco set I have, they were both the same. I have an NOS front cylinder being mailed to me to compare against that. Both front wheel cylinders were leaking at the same spot, the crush washer. So, it's either the washer or the rubber line. I did try two sets of rubber lines.

The NAPA's I put in were smooth as you mention.

The mystery continues!

[Joe L.]

Re: 1963 - 1965 Front Wheel Cylinders

Dan, I looked at that. I compared the two, to another Delco set I have, they were both the same. I have an NOS front cylinder being mailed to me to compare against that. Both front wheel cylinders were leaking at the same spot, the crush washer. So, it's either the washer or the rubber line. I did try two sets of rubber lines.

The NAPA's I put in were smooth as you mention.

The mystery continues!

Harry-------

The wheel cylinder-to-brake hose seals at the copper washer. The same is true for caliper-to-brake hose for 1965-82 front calipers.

Hydraulic brake systems operate, of course, at very high pressure when the brakes are applied. So, the sealing is challenged. The sealing surfaces of the wheel cylinder/caliper and brake hose fitting flange are critical and need to be perfect. You will note the "concentric rings" seen on the wheel cylinder/caliper sealing surface. This is an important part of the sealing function.

The other critical part of the sealing system is, of course, the copper washer. Sometimes this is taken for granted. However, this washer needs to be dead soft copper and not some harder copper alloy. I think that some of the copper washers "out there" are too hard and will not seal well. The original copper washers dating back to 1953 and used on Corvettes through 1982 were GM #231343. However, this part has been discontinued without supersession.

[Harry S.]

Re: 1963 - 1965 Front Wheel Cylinders

Harry-------

The wheel cylinder-to-brake hose seals at the copper washer. The same is true for caliper-to-brake hose for 1965-82 front calipers.

Hydraulic brake systems operate, of course, at very high pressure when the brakes are applied. So, the sealing is challenged. The sealing surfaces of the wheel cylinder/caliper and brake hose fitting flange are critical and need to be perfect. You will note the "concentric rings" seen on the wheel cylinder/caliper sealing surface. This is an important part of the sealing function.

The other critical part of the sealing system is, of course, the copper washer. Sometimes this is taken for granted. However, this washer needs to be dead soft copper and not some harder copper alloy. I think that some of the copper washers "out there" are too hard and will not seal well. The original copper washers dating back to 1953 and used on Corvettes through 1982 were GM #231343. However, this part has been discontinued without supersession.

Thank you, I'm on the hunt......

[Dan D.]

Re: 1963 - 1965 Front Wheel Cylinders

Harry-------

The wheel cylinder-to-brake hose seals at the copper washer. The same is true for caliper-to-brake hose for 1965-82 front calipers.

Hydraulic brake systems operate, of course, at very high pressure when the brakes are applied. So, the sealing is challenged. The sealing surfaces of the wheel cylinder/caliper and brake hose fitting flange are critical and need to be perfect. You will note the "concentric rings" seen on the wheel cylinder/caliper sealing surface. This is an important part of the sealing function.

The other critical part of the sealing system is, of course, the copper washer. Sometimes this is taken for granted. However, this washer needs to be dead soft copper and not some harder copper alloy. I think that some of the copper washers "out there" are too hard and will not seal well. The original copper washers dating back to 1953 and used on Corvettes through 1982 were GM #231343. However, this part has been discontinued without supersession.

I think Joe hit the nail on the head, as the hardness of the copper washer is most likely the problem. It is the only thing that is different, and the washers we buy are mostly not specified to be dead soft, and no one would know that this would be so important in this application.
Also, we usually like to tighten, loosen, tighten several times to help flare type fittings seal better. That probably is not a good idea with these concentric rings. If the washer rotates a little when loosening and tightening, then you have made groves in the washer and it is not going to seal.

By filing it flat, I must have done a good job of making it flat, but I have ruined the originality of this wheel cylinder forever.

Could one anneal these washers to be softer? I have an old toaster oven I use for baking small parts, and it will go to 450*.

Dannn