81c3

Some parts houses are showing the single reservoir for 86-87 and the double reservoir for the 88. Mines an 86 and has the double reservoir.... not the single. What gives? Should I order the 88 regardless?

Others show the 85 having the double reservoir also!!!

So my 86 has a production date of 11/85 so it looks like maybe an 85 master cylinder would be my choice... Opinions? I want to get this stuff ordered. Now that my local parts house let me down with wrong brake hoses Im getting everything on line...

WVZR-1

There's very likely casting information on the actual cylinder. I'd maybe do my research from that point and attempt to ID what was "maybe" used as a replacement at some point.

Does it actually need a master?

I don't know that I'd go on-line just because of a bad experience at 1 local. What was the "bad experience/let down" regarding hoses?

****I'm quite confident that the dual reservoir could be used on any of the original PBR cylinders with the correct grommets. Depending upon the source/brand of the master you actually buy you may not get reservoirs.

gerardvg

Hi

Yes the early c4's got the dual reservoirs, personally I prefer that.
Say one brake hose bursts...... you would quickly loose al your brake fluid on a single reservoir type, the twin reservoirs will mean you have functioning front or rear brakes if one lost all its brake fluid.

You can easily fit the dual reservoirs on later master cylinders.

81c3

I didnt think Id get the reservoirs, and planned on using the old ones. I think the master is original, car has only 34k miles on it, but is 31 years old. Brake hoses seem very hard, so I was wanting to replace all 4.

As far as the parts house here, I returned everything I bought already. Ive decided to go with more of a specialized Vette supplier. I showed up to pick my parts up, one box was completely empty... strike one! Get home and the first brake hose doesnt fit into the bracket where it meets the line..... strike 2... Not willing to go to strike 3... returned all the parts!

81c3

So, the 85 version looks like its exactly what I have... Both Corvette Central and Ecklers show the 2 res for 84-85 86-87 show 1 res 88 again shows 2.... being the car was built in 85, Im thinking its safe to go with the 85 version.

WVZR-1

Good damn "luck" with a "specialized Vette" supplier

Their product is whatever the vendor sends them and there's no further QC steps as to "what's in the box"!!

I haven't done an early brake hose replacement but all of the later were "indexed" for proper installation at the frame brackets. Even though the '84 - '87 are the same R & L, I'd still think they're indexed for the bracket. Did you maybe try a rear on the front or a front on a rear?

I'd certainly attempt to ID the master by casting information. An '86 is first year for ABS and there's piston difference mentioned in the master cylinder. Does it matter? Who knows.

What you "THINK" is maybe irrelevant! Check the casting numbers!

81c3

No, I had the front hose... the rears are noticeable different.

So, when I get the casting number, what do I compare with?

81c3

Corvette Central suggests I get the one for the 86-87 and put on the 2 separate reservoirs if I want to... but he pretty much insisted I go with the 86-87 master....

WVZR-1

If the master is still on the car I believe you can read the PBR casting with a mirror. I'd expect you to find K212-024C-? - where ? is likely a number.

Many years ago I ID'd all of these masters for Ralph (Indianavette) and a couple years ago I lost a HDD on a PC that very likely had all of that information. I'm unable to put my hands on it today easily but I may look later.

It wouldn't have been unusual for someone when these cars were newer to replace the reservoirs with a "PAIR". I believe that Cliff actually did that with his '86. The reasoning is that it would be easier to "eye-ball" the levels and if there were a problem was it front or rear maybe!

If I stumble upon my list and references I'll post back.

I'd give the locals another shot at the hoses. Which auto parts store?

Do be in such a hurry to get pi$$ed - you've got old to show them the indexing if there is one so ....

Post a snapshot of the end of the hose where it's retained to the frame bracket. I'd be interested in seeing how it's indexed. Since it fit both sides I believe I understand but it might be an interesting snapshot. '88+ are indexed very differently and they're selective L/R etc.

81c3

Ill get the info when I go home for lunch. When I mentioned casting numbers to the Corvette Central rep, he said it wouldn't be of any help to him.

81c3

The only numbers I can find are as follows, and just like I have it:

#258
11-2012

WVZR-1

Nothing that I'm familiar with as OE. Does the master have PBR cast into it very near the hydraulic fittings?

81c3

No...

WVZR-1

Isn't OE/GM then so the purchase of "what-ever" is maybe a coin toss!

I believe were it me I'd buy the '86 and maybe use your reservoirs as an option!

I'd be very inclined to do a "local" - hoses "local" also!!

Joe C

(my 2-cents, FWIW) from what I understand, all 84-91 OE master cylinders have the same casting numbers - K212-024C-X. for the X, my 85 ends in a "6" and my 90 ends in a "5," the last number might have some production significance (???) all had dual reservoirs except model years 86 and 87, and all assemblies have a different primary and secondary, or F/R, outlet sizes - 10mm and 12mm. all years had a 7/8" bore size w/ two mounting holes. i'm thinking new, OEM, PBR assemblies are no longer available. if I were looking into replacements, I'd look at new RAYBESTOS assemblies, part number, MC39621, for a single reservoir, and RAYBESTOS, part number, MC39524 for a dual reservoir. personally, i'd go with the dual reservoir assembly.

81c3

Amazon has that part number for only 99.00.... Its 191.00 from Ecklers.....

Cjunkie

1 or 10 reservoirs doesn't matter, its the bore size that counts.