The 1947 - Present Chevrolet & GMC Truck Message Board Network

The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)

- The 1967 - 1972 Chevrolet & GMC Pickups Message Board (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=3)

- - Power Master Cylinder (https://67-72chevytrucks.com/vboard/showthread.php?t=775463)

rcazwillis

11-18-2018 08:03 PM

Power Master Cylinder

Anyone know if any parts stores have power master cylinders. The one from NAPA was a manual. Their parts list did not distinguish power vs manual. Tried one, manual. Oriellys does not distinguish.

I know online vendors have it, like to buy these type of items local.

jocko

11-19-2018 10:16 AM

Re: Power Master Cylinder

They should have both. I like to buy this kind of stuff local also - much easier to return, which seems to be necessary all too often. I believe the only difference between power and manual mc for a given configuration is the depth of the pushrod hole in the piston. If I recall, the power mc has the shallow hole and the manual mc has the deeper one, but it’s been awhile... How did you determine the one you got was a manual rather than power? I’m pretty sure last one i did this I got it at OReilly - for a 71 C20.

LockDoc

11-19-2018 11:05 AM

Re: Power Master Cylinder

1 Attachment(s)

-
This Raybestos master cylinder (RMC39075) is listed as being for a 3/4 ton with power brakes. Here are the cross reference numbers for other suppliers. I don't know how current this list is or if part numbers are still good.

rcazwillis

11-19-2018 10:12 PM

Re: Power Master Cylinder

Quote:

Originally Posted by jocko (Post 8387317)

How did you determine the one you got was a manual rather than power? I’m pretty sure last one i did this I got it at OReilly - for a 71 C20.

The deep hole in the plunger. Oreilly said they would order them to see what works. May go with that option.

rcazwillis

11-19-2018 10:13 PM

Re: Power Master Cylinder

Quote:

Originally Posted by LockDoc (Post 8387348)

So the 3/4 ton should be the same? I was wondering if there was a difference.

jocko

11-19-2018 10:27 PM

Re: Power Master Cylinder

3/4 ton and 1/2 ton mc's are not the same. On a 3/4 ton mc in 71 (I assume this is for your 71?), the forward port is for the rear brakes and the rear port is for the front brakes - opposite of the 1/2 ton mc. Yes, the 1/2 ton mc is more intuitive, but that's what ol uncle GM did. You need to specify 1/2 vs. 3/4 ton as well as power or manual when buying to make sure you get the correct one.

rcazwillis

11-19-2018 10:50 PM

Re: Power Master Cylinder

Yes on the 71. I ordered the part from Classic Parts last night along with front hoses. Hope they are long enough.

Thanks for the quick response on the 3/4 vs 1/2. I assumed they were different.

LockDoc

11-20-2018 01:05 AM

Re: Power Master Cylinder

Quote:

Originally Posted by rcazwillis (Post 8387878)

Yes on the 71. I ordered the part from Classic Parts last night along with front hoses. Hope they are long enough.

Thanks for the quick response on the 3/4 vs 1/2. I assumed they were different.

That's why it is always a good idea to state in your first post what you are working with.....

LockDoc

demian5

11-20-2018 05:08 PM

Re: Power Master Cylinder

This is a great way to look up parts along with rock auto.

http://www.centricparts.com/

All times are GMT -4. The time now is 01:14 PM.