I need to r&r my rear brake calipers on my '89 740. Ain't had no luck finding anything but the 38mm calipers but i need 34mm. Any ideas?

 

the parts catalog doesn't show any 34mm, just 36, 38, and 40....

it has the following PN's for Volvo rear brake calibers on a 1989 740...

3530755 marked 36 - LH
3530756 marked 36 - RH
5003512 marked 36 - exchange LH
5003513 marked 36 - exchange RH

3530757 marked 38 LH
3530758 marked 38 RH
5003514 marked 38 exchange LH
5003515 marked 38 exchange RH

9140392 marked 40 LH
9140393 marked 40 RH

 

It's clearly marked 34...i did a search to see if a 36 could be used instead of 34 and came up with a vendor that had 34 listed for sale for a 1984 740. I'm thinking / hoping that will work. All the national part chains have 38 and 40 they can order but no 34 listed...kinda like what you wrote about part numbers.

 

maybe you can put whatever is the more common on later cars, along with the matching rotors? I dunno why that wouldn't work. but then, wait, they all use the same rotors, so I dunno what the 34-36-38-40 refers to?? huh. later years were just 38 and 40

 

My 89 740 GL has 38's on the rear. FYI

 

I don't understand why they aren't interchangable. the mount plates on the ends of the axles are the same, there's only one PN for brake pads and for rotors.

 

+1 pierce.

I'm pretty sure they're interchangeable. I once pulled a rear brake off an 850, and put it on my 240 as a temporary measure. It worked just fine, and I thought about leaving it as a permanent change. But the compulsive side got the better of me.

 

the only thing i *would* suggest is, be sure both sides are the same.

 

Yeah... I've come to believe that they are interchangeable. I believe the markings (34,36,38,40) refer to the piston size. And so long as both sides are the same you're ok. I ended up being able to use the 34's and now have a pair of 38's in the basement. Thanks for all the replies and your help.

 

yes on the cylinder size. the 'repair kits' are specific to the stamped number, 36, 38, and 40 as the choices listed.

i don't see any cylinder size specific parts in the brake circuits, i thought maybe the proportioning valve might be different.