ok guys my left front wheel cylinder went out today and i went to the local advance auto parts. They had two sizes 1 3/8 bore and 7/8 which one is correct for 72 cutlass s with power drums. i know the bigger bore will have more braking power which my car could use is this something i should consider if i have the 7/8 bore wheel cylinders the car has kind of weak brakes with the cam thats in there . i had the drum off but i didnt know there where two bore sizes so i figured i'd ask before taking the drum off again . most people would just take the part and compare it but i have limited work space in a one car garage and i dont like leaving my car out on jack stands so i have to get it right the first time and plan it out . Any help or advice is greatly appreciated .

 

Can you get both and return the one you didn't use?

With cars that are this old, you never know who has put what on them.................

 

well i dont know what bore size i have im trying to see what was standard on those cars i bought the 1 3/8 thinking power drums needed the bigger bores but i might be mistaken i might need the 7/8 either way im poping the drum off again tommorow and comparing it to the one i got if its smaller ill switch that one out if not its goin in only the one wheel cylinder went out and its only leaking . but im also trying to see if i can use the 1 3/8 as an upgrade to get some added stoping power., either way ill probably end up just replacing the one thats bad with the size that came out

 

According to the parts book, original was 1.125". Some earlier A bodies used 1.06" diameter wheel cylinders.

 

im going to take the drum back off and double check i looked in the auto zone computer and it only showed the 1 3/8 cylinder., i might not have the right size but i got the bigger of the two available. im guessing the smalle bore is for non power drums ????

 

No, the front were the same for PB andd MB; rear cylinders were .875" your year; some other years had rear cylinders in .81" or .93" diameter.

 

thank you seems like i got the correct one and i do have the 1 1/8 or 1.125 . i just needed the clear that out., i would hate to take the drum off again just to find out i bought the wrong one.

 

7/8" are for the rear -- the young whiipersnapper is not well versed at reading a catalog -- should stick to selling oil and air fresheners.......

Call me if you have any concerns -- I have the front shoes, front wheel cylinders, front brake hoses, front wheel bearings & seals, and front drums ---- all American made!!!!!!!!!!

Craig -- 516 - 485 - 1935.................

 

Thank you for the help I got it fixed on sunday I forgot to update everyone on it I did get the right one I figuerd the bigger one was for the front so that's what I went with