First use of bleeder valves for wheel cylinders?

[Bob B.]

Hi all,

Someone sent me this pic of one of his wheel cylinders (1959). As the picture shows, there is no bleeder valve. Instead, there is a plug that must be removed and then replaced after bleeding. He thought this was correct on early Corvettes.

Anyone know if these were used any time in the past for any car and, if so, when was the switch made to bleeders that just need to be loosened as we have now?

Thanks,

Bob

[Jim L.]

Re: First use of bleeder valves for wheel cylinders?

Hi all,

Someone sent me this pic of one of his wheel cylinders (1959). As the picture shows, there is no bleeder valve. He thought this was correct on early Corvettes.

That looks like Bubba's work to me. I've never worked on an old Chebby that didn't have bleeder valves.

Jim

[Ernie F.]

Re: First use of bleeder valves for wheel cylinders?

That looks like Bubba's work to me. I've never worked on an old Chebby that didn't have bleeder valves.

Jim

Bubba at his best! I've had chevys from a 49 up to 07 and never seen a plug used. Man that would take some creative bleeding too! "Hold the pedal down, keep holding, keep holding, no don't let up, keep holding! OK. . . Got it, pump. . . Keep holding!

Ernie

[Duke W.]

Re: First use of bleeder valves for wheel cylinders?

That thing between the two attaching screws sure looks like a bleed valve to me!

The unused "pad" may simply be for applications that have the input lines on the same side, so the casting can be used for both right and left sides in applications where the input pipe comes in at the front or rear rather than perpendicular at the center.

Duke

[Ian G.]

Re: First use of bleeder valves for wheel cylinders?

I think its original. I have a 821 wheel cylinder in the Delco Moraine tin can that has a bolt that goes into the bleeder valve, instead of a regular one-piece bleeder valve just like what that looks like in Bob's pic. There should be an external tooth washer there that is missing. CC sells them also:

191015 BRAKE BLEEDER VALVE SET - 3/8" 24 - 4 PIECES

It would be hard to bleed them though, since the attachments are rubber. maybe in the 50's they had a screw-in hose?

[Perry M.]

Re: First use of bleeder valves for wheel cylinders?

That's the way it is on my 57 Nomad. The screws are simply plugs. The larger hex head is the bleeder.

[Jim L.]

Re: First use of bleeder valves for wheel cylinders?

I think its original. I have a 821 wheel cylinder in the Delco Moraine tin can that has a bolt that goes into the bleeder valve, instead of a regular one-piece bleeder valve just like what that looks like in Bob's pic. There should be an external tooth washer there that is missing. CC sells them also:

191015 BRAKE BLEEDER VALVE SET - 3/8" 24 - 4 PIECES

It would be hard to bleed them though, since the attachments are rubber. maybe in the 50's they had a screw-in hose?

I stand (or type, in this case) corrected. Yep, that's a bleeder valve, the larger hex being the valve. And to use it without making a mess, you would indeed screw a fitting into the valve in lieu of the bolt.

I've never seen such a thing.....

Thanks to the OP for the posting.

Jim

[Gary C.]

Re: First use of bleeder valves for wheel cylinders?

Bob, hex head bolts were used at least through the '57 MY for Corvettes. Not sure when the General started using bleeder valves. The revised 56-7 JM is going to state that hex head bolts were used. Gary....

[Ian G.]

Re: First use of bleeder valves for wheel cylinders?

I'll see if there's a date on my Delco tin can. The cylinder is a 821 inside.

[Gary C.]

Re: First use of bleeder valves for wheel cylinders?

'58 P&A shows Group # 4.666 part # 5454315, 10-32x1/4 inch hex head bolt. 61 P&A shows a bleeders. Didn't take my 59-60 books out to check. Gary....

[Ian G.]

Re: First use of bleeder valves for wheel cylinders?

cool deal. Saved by the book

[Joe L.]

Re: First use of bleeder valves for wheel cylinders?

That's the way it is on my 57 Nomad. The screws are simply plugs. The larger hex head is the bleeder.

Perry-----

That's correct. The screws are simply plugs. The bleeder operates in the usual manner after the plugs are removed. Later bleeders used an integral nipple instead of the screw/plug. Some of these had a rubber snap-on cap, but I don't know if later C1's equipped with this type bleeder ever used these.

So, when did the change occur during the C1 period? I can say that, for sure, the early style (i.e. with screw plug) was used through 1958. However, I don't know, for sure, when the later style began. I believe it was either for the 1959 or 1961 model year, though, or, perhaps, sometime in between.

[Jim L.]

Re: First use of bleeder valves for wheel cylinders?

So, when did the change occur during the C1 period? I can say that, for sure, the early style (i.e. with screw plug) was used through 1958. However, I don't know, for sure, when the later style began. I believe it was either for the 1959 or 1961 model year, though, or, perhaps, sometime in between.

I just checked my '59-'60 passenger car shop manual. The manual makes it clear that the change was in place by '60, equally clear that the screw plug style was still being used in '58, and ambiguous about what was in use in '59.

Jim

[Gary C.]

Re: First use of bleeder valves for wheel cylinders?

59 P&A shows bolts, 60 P&A shows bleeders in group 4.666 Gary....

[Bill M.]

Re: First use of bleeder valves for wheel cylinders?

I just dug my '59's original wheel cylinders out of the "junk" pile, and they have the bolts. My car is 2528.