[Leonard Welch]

I removed my master cylinder and brake booster for refinishing. It looks like the master cylinder was replaced at some point. Since the car was originally equipped with power front disc brakes, the master cylinder should have bleeder valves. Mine doesn't have the bleeder valves and has the the following information on the bottom of it:

28876
USA
GL - 12
91/8

It looks exactly like the one offered here:

http://cgi.ebay.com/ebaymotors/ws/eB...&category=6033

...so it leads me to believe that this is a GM replacement master cylinder. My books tell me that the original master cylinder number is 5471802 with cover 5470405. The original master cylinder look like this one:

http://pages.cthome.net/lenbo/71gtoengine7.jpg

First question - aside from originality - is there any performance reason that should cause me to replace the master cylinder with an original? Looks like the only functional difference is the bleeder valves.

People tell me that they've recently bought new correct master cylinders - with the bleeder - valves from Napa. When I went to the local Napa, Autozone and Advance Auto Parts stores in my area and showed them a picture of the AC Delco unit that I have, they all said 'nope'. I then let them look it up by vehicle. I never thought to check their 'aftermarket units.

But thinking of Napa, I found the following master cylinders on their site (www.napaonline.com):

NAPA United Brake Master Cylinder - New - UBP = 36318 $ 169.00
w/ Power Brakes, Moraine Cylinder

NAPA United Brake Master Cylinder - New - UBP = 36361 $ 81.99
w/ Power Brakes, Bendix Cylinder

Safety Stop Brake Master Cylinder - New - USS = 4736361 $ 41.49
w/ Power Brakes, Bendix Cylinder

Tru-Stop Master Cylinders Brake Master Cylinder - Remfd - TSM = 101521 $ 17.99
Core 5.00 w/ Power Brakes

I called the local Napa to ask if they had any of the above in stock. No. The United brands are direct orders from the factory - so I'd have to pay first. If they're incorrect, they'd charge me a fee to return them. Originally, I was thinking that the correct unit would be one of the United brands. However, they're much more than the $35-$40 range that has been mentioned. Given all this, does anyone know of the 'correct' master cylinder part number and/or source? Napa or otherwise?

[Leonard Welch]

I removed my master cylinder and brake booster for refinishing. It looks like the master cylinder was replaced at some point. Since the car was originally equipped with power front disc brakes, the master cylinder should have bleeder valves. Mine doesn't have the bleeder valves and has the the following information on the bottom of it:

28876
USA
GL - 12
91/8

It looks exactly like the one offered here:

http://cgi.ebay.com/ebaymotors/ws/eB...&category=6033

...so it leads me to believe that this is a GM replacement master cylinder. My books tell me that the original master cylinder number is 5471802 with cover 5470405. The original master cylinder look like this one:

http://pages.cthome.net/lenbo/71gtoengine7.jpg

First question - aside from originality - is there any performance reason that should cause me to replace the master cylinder with an original? Looks like the only functional difference is the bleeder valves.

People tell me that they've recently bought new correct master cylinders - with the bleeder - valves from Napa. When I went to the local Napa, Autozone and Advance Auto Parts stores in my area and showed them a picture of the AC Delco unit that I have, they all said 'nope'. I then let them look it up by vehicle. I never thought to check their 'aftermarket units.

But thinking of Napa, I found the following master cylinders on their site (www.napaonline.com):

NAPA United Brake Master Cylinder - New - UBP = 36318 $ 169.00
w/ Power Brakes, Moraine Cylinder

NAPA United Brake Master Cylinder - New - UBP = 36361 $ 81.99
w/ Power Brakes, Bendix Cylinder

Safety Stop Brake Master Cylinder - New - USS = 4736361 $ 41.49
w/ Power Brakes, Bendix Cylinder

Tru-Stop Master Cylinders Brake Master Cylinder - Remfd - TSM = 101521 $ 17.99
Core 5.00 w/ Power Brakes

I called the local Napa to ask if they had any of the above in stock. No. The United brands are direct orders from the factory - so I'd have to pay first. If they're incorrect, they'd charge me a fee to return them. Originally, I was thinking that the correct unit would be one of the United brands. However, they're much more than the $35-$40 range that has been mentioned. Given all this, does anyone know of the 'correct' master cylinder part number and/or source? Napa or otherwise?