Jet front brake cups

Jet front brake cups, what size do I buy?


  • Roy,

    Unless the photo is incorrect, that Centric cylinder won't interchange with the Jet front. It's a 1-1/8 dia., alright, but the similarity ends there. Best bet is to have yours sleeved but, as Ken says, keep your hands on the pistons and boots. Cups are common.....the rest isn't. Attached is a photo of a Jet front cyl.  Note the relative position of the bore centerline to the mounting. There is a 1-1/8" cyl. that looks similar (I don't recall the application off-hand) but the bore is in a different location (vertically speaking)  and won't work.

    Rear is a similar story and there is a replacement available but, again, keep a firm grip on your pistons and boots because the new one (NAPA 36029) is designed for a brake using "shoe links" so the boot is different from the Jet, which has the shoe-end bearing directly on the steel button pressed into the Aluminum piston. The boot is NAPA UP 5994 in case you need to replace yours. The new rear cyl. will not have the correct piston but the machined casting is identical.

    Repair kits for the front are listed as UP 164 but won't give you the Al pistons. Rear kit available (NAPA UP 170) but I wouldn't waste my time rebuilding one when the new one is cheap and you must use your old pistons in either case.  Left and right are the same cyl. on rear but not front.  

    None of these parts are "on the shelf" ordinarily but you should be able to order them.


  • Roy,

    Just a heads-up, the Jet cylinders listed on Rock Auto's site are not correct.

    The numbers I've shown are NAPA p/ns but may be crossed to whomever you may prefer.


  • It is correct (compare my end-view to theirs) ......but good luck finding them.  I've been through this before, even talked directly to Dorman who said some day they might make another run of those (L & R are the same except for opposing hose connections).

    I found one at the Colo. Sprgs. Nats (Thanks Stu!) and gobbled it up immediately, but have never run across any before......or since. If not for it being a low demand brake system part, I'd make them myself.

    I once checked with a local supplier whose computer showed one. It was $65 + freight-in. I grabbed it only to find that someone had switched the box contents with some common cylinder. Damn! The box was correctly marked. I got my $ back on the part but they made me eat the shipping. I won't forget that.

    Bottom line: Don't let loose of your front or rear pistons, have the fronts sleeved and get the new rears. Kits for both have the boots as well (from NAPA, anyway), but I find availability to be challenging. A few distribution centers show them at various places around the country and the NAPA Supplier shows them, so they should exist. Rock lies occasionally. Their shoes appear to be correct.

    The Amazon parts have a note saying "We don't know when or if these parts will be back in stock". I think I do.


  • 53jetman
    53jetman Senior Contributor
    Rock Auto,  about a year ago considered the #55 brake shoe for the Jet.  I drew their attention to the fact that it was not a correct application at that time.  Apparently they did make a change in the shoes they were recommending if you say they now have the correct shoe #51 available.
  • In my previous post, I had commented on the incorrect listing for the shoes but deleted it after a "fact check". If they have changed to the #51, they should be correct. Their photo appears to bear that out.


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