Can I trust Rock Auto if I purchase a master cylinder from them. 1968 PB car? I have heard that parts stores are selling a one size fits all 68-82 master that is not correct. Thanks.

 

It should not be a problem if you specify an AC Delco master cylinder for a power brake car. #18M27. The bore size is 1.125".

 

The issue is usually with the plunger being the correct depth with the booster. I gave up trying to deal with it and bought the booster and master as a set. Less issues
And you have to specify disc / disc, some vendors have drum/drum, disc/ drum and disc/disc as options

 

If you are going to keep the car I would consider a Wilwood (sp?) or another better/Higher quality preferably a new unit in place of a re-built. The brake system of a Car is a CRITICAL system and it HAS to work when you need them to work. Why save money on cheap parts when better parts are available

IF you have the time I would get your particular car's master cylinder rebuilt and then re-install it. From people I know who have rebuilt them it is not too hard. Volunteer Vette sells their rebuild kits for $36.99 and with home tools you should be able to do it yourself.

TOO many parts coming from places that sell "Re built" equipment are PURE Junk. I bought an Alternator from Pep Boys and it lasted less than 5 miles before the bearings popped out. I bought a Power Steering pump that developed a killer leak in less than 2 days.

Rock Auto has bitten me twice and both times they were electrical parts. They have some great parts for the price and some trash for the same price. I ordered a MAP sensor for $~15 and when I had mine removed and was ready to install the new part, I then learned that some creative twerp swapped new for old and mailed the bad sensor back as a Return saved them selves ~$15 and delayed my fixing my car. I tried to return it after telling them it came :used" then they suggested that I was trying to pull a fast one on them and voided the return.

In all honesty I just bought the entire brake system from ROCKAUTO including Calipers, Rotors, Hoses, seals and new Brake Pads for less than $80 with Girling brand parts. This was a great sale and I took advantage knowing the quality of the parts from experience. I am going to be more careful buying anything electrical from them.

 

Thanks for all the replies. I am going to have the original date coded master rebuilt over the winter. But I wanted to replace what I have on there now for the time being.

 

You mean 18M72 not 27?

 

The question is, do you want a "functional" replacement or a original looking one?
They both work fine, but may look different. A lot depends on how much $$ you want to spend.
From my personal experience, I will never buy a rebuilt mc again.
But then again, the new ACDelco I bought 6/7? yrs ago had a made in china tag on it. It looked good but only lasted a few years and low miles, then went bad. I now have a newly made reproduction from Corvette Stainless Steel Brakes in Florida that looks good and is still working fine after 4/5 yrs and 5k? miles.

 

I would not buy any MC mail order.
You need a visual of the end of the MC. The piston and the flange.
You need to compare the new with the old and that is not an option unless Rock-Auto has free return shpg.
The safest and most efficient way to buy an MC is to take your old one with you to your favorite trusted store and put the new / old side-by-side on the counter.
If it's a perfect match, then decide if you want to forfeit your core or hang on to it, for future rebuild perhaps?

 

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Cssbinc and tuffstuff....pay attention to the barake system.....disc/disc