c20 disk swap master cylinder

[paulbrgr9999]

I am reading in posts that the origional mater cylinder on my 1970 c20 can still be used after the swap (which we did this past weekend). All I need is a proportioning valve.

But when I look at the master cyliner on the 72 front end I bought it looks much larger than the master on the 1970.

So finally my question: can I use the old master off the 1970 or should I buy a brand new master with proportioning valve for the now 1972 front end?

I do have power brakes if that matters.

[Livrat]

You need to use the 72 master cylinder, proportioning valve and booster, (the 72 disc brake master cyl will not work on the 70 C20 booster)

[69worktruck]

I would use the new MC from the 72 along with the combination valve. You may have to run a new brake line from the combination valve if your front brakes currently use a splitter. I would also check the power boosters between the two and if different, use the power booster for a 72 with power disc brakes.

My swap was off of a 78 C30, I kept the original power booster, the brakes work well but the pedal is low and hard...I plan on making the power booster swap soon.

[paulbrgr9999]

Originally Posted by 69worktruck

I would use the new MC from the 72 along with the combination valve. You may have to run a new brake line from the combination valve if your front brakes currently use a splitter. I would also check the power boosters between the two and if different, use the power booster for a 72 with power disc brakes.

My swap was off of a 78 C30, I kept the original power booster, the brakes work well but the pedal is low and hard...I plan on making the power booster swap soon.

Thanks for the response. Did I read a post by you about having a problem with the alignment after your swap? I read a lot of posts about the brake swap and cant remember details like who posted.

thanks

[69worktruck]

I am having alignment problems. From what I have read here and elsewhere, this is not common with the swap that I did so I am leaning toward the spindles that I used as causing the problem.

[paulbrgr9999]

Ok, wish I could help you with that but i dont know much about alignments. I have never until last weekend done anything more complicated than a tune up and oil change. I hope i will not have the same problem. We put back exactly the same number of shims that were there origionally. The truck will go in for an alignment next week I hope. We have to get the master, prop valve, and booster in first.