Questions---Master cylinder and rotors

[70c10]

First question- when you install brand new rotors do you have to resurface the face of the rotor before installing?. I'm thinking it's not necessary.

Second question- I picked up my master cylinder last night for a 71' C/10 and want to make sure this is correct. Mine is the one with the gold cap but I have also seen people on here with the one that has the silver cap. Will the one they gave me work???

Thanks!

[underdog8704]

i have a 71 with the same cap. i have recently been looking for a gasket for the cap with no luck. the only ones i can find are in the gold cap's shape.

[70c10]

Does your 71' have the style in the pic on the left or right?

[byrd]

Jim,
I would not resuface the rotors should be striaght anyway, a good cleaning with BPC should be just fine.
my booster and master combo that I have for my 69 has the same master as the one on the left.

[cdowns]

i like to gently block sand new rotors with 220 sandpaoer and then clean with brake clean

[msgross]

Originally Posted by cdowns

i like to gently block sand new rotors with 220 sandpaoer and then clean with brake clean

ditto, be sure to put that "anti-squeal" stuff on the back of your pads too! Less vibrations that cause squealing....

[Zonaman]

Just converted my 69 to front disc brakes. Used brake cleaner for the new rotors, that's all. While we're at it, is the booster (1/2 ton) for drum the same as disc? Look the same to me. I know the proportioning valve is different.

[70c10]

Thanks for the replies guys!

[underdog8704]

i have the one with the silver cap. it is supposedly original. the gasket needs replaced due to some leaking, but i cant find a new one. where did you get your master cylinder from.

[70c10]

I got mine at Autozone.

[Longhorn Man]

It is a very good idea to roughen up the rotors, we take diegrinders and hit both sides of the rotor, just a scuffing, not actually to remove a lot of material. The indy car teams all do this, it helps to bed the pads in quicker and better stopping is the result.
As for your master cylinder, are both resivours the same size? I'm willing to bet the one you have is original to the truck...when it had drums. Disk brake masters should have a much larger resivour for the front brakes since the calipers uses fluid to adjust the brakes.

[70GMCer]

Jim call me up today.....Don't do anything to those rotors!!

[Draggn66]

Originally Posted by Longhorn Man

Disk brake masters should have a much larger resivour for the front brakes since the calipers uses fluid to adjust the brakes.

Sooo what would the symptoms be if the wrong MS was installed? My 71 has disc brakes. The MS that was on there when I got it was like the one on the right. When I replaced it with one I bought at Napa they gave me the one on the left.

[Boog]

There are many varied opinions on new rotors and drums. I feel like a brand new part should be ready to install right out of the box. Several guys have told me they never put one on without trueing it on the grinder first. I have put on a few new rotors and drums. I ended up having to have them cut to get the pulsing pedal out of it. These were bought from CarPro and Napa stores. And they were Chinese. Maybe a new genuine GM rotor or drum is true right out of the box, I don't know.
At the very least maybe you should mount them and put a dial indicator up against them to check the runout before putting it all back together.

[A.P.]

For new rotors, I just clean with brake cleaner and install them. Only when replacing brake pads I resurface the rotors. Recently I replaced the MC for my 72 chevy truck and it uses the one on the right, but I could not find the original. I ended up using the one on the left. So far I had not any problems. But then again I don't use my truck as a daily driver.

A.P.