Power Brake Booster question

[jocko]

In the process of ordering a bracket from Captain. Choosing a brake booster also. Does anyone know the difference between a JM3, JM5, and JM7 stamped power brake booster? See link at Oreilly's to see what I'm talking about. They "look" different, all have about the same application data (for an S10). Just curious...

The 3 I'm talkin about are the boosters only (ignore the master/booster combos on the page) -

http://www.oreillyauto.com/site/c/se...S10&vi=1060883

(btw, Captain, JUST got your pm thanks - I think you're correct - dual vs single diaphragm - just curious why S10 would have had both options, but who knows).

[Captainfab]

Here's about the best description I found....

http://www.c2e.info/rpocodes/gmrpocodesGthroughM.html

I imagine there are some dimensional differences also.

There's some other useful info there on GM RPO codes.

[dlisabeth]

I would suggest that you use a master cylinder off of a c10 instead of an s10. I tried to use both the booster and mc off a '97 s10 and ran into problems because the s10's mc couldn't push enough fluid. As soon as I switched to a mc off an '85 c10 the problem was solved and the brakes were firm. I am running stock drums in the rear with discs in the front off of an '85 c10. I am still using the s10 booster so you should be fine there.

[jocko]

Thanks Capt and dlisabeth, good gouge. The RPO codes are helpful - and this helps me decide between C10 and S10. I think at this point, I'm actually leaning toward a 75 imp booster - should bolt directly to Capt's bracket and also will work with the master cylinder i'm getting.
thanks again for the help.