I’ve put a early Bronco 9” rear end under my 41 pickup build. Small bearing, 10” brakes. When I ordered all new brake parts (from RockAuto), I naturally ordered the wheel cylinders. The index shoulder on them is too small for the 1.5” backing plate hole, plus it’s a small diameter bore. Part number is correct by their listing. I had some other 9” wheel cylinders with the correct 1.5” seat index and they bolt right in, but are 15/16”bore. The backing plates are original to the rear end, so WTF gives??? Two different wheel cylinders for the same dia. brakes? Power vs. non-power? It’s little stuff like this (and still not having the fronts from ECI) that are flat wearing my ass out! Of course, they’re not returnable as I’ve had them over 30 days. Any input appreciated guys! Bill
wrong parts in the boxes.. Happens all the time. They should be a 15/16th bore Buy another set. If bought from a local big box store you could have returned them for a Xchange. Wheel Cylinder - 1976 Ford Bronco | O'Reilly Auto Parts
It might have something to do with the big and small bearing Bronco rear axles, man I wish Randy was still with us, he was very knowledgeable on the Bronco rear axles. HRP
JYD......Yep. Hindsight is 20/20 in my case. At least they were cheap. HRP.....Large bearing rears had 11” brakes, small bearing had 10”. Backing plates are 10”, but w/c hole is large, LIKE 11”.
If the wrong part was in the box, I would just reorder, then swap them and do a return. Be sure to tell them the wrong part was provided in the box so they do not just give them to the next guy, though I have seen this happen many times at big box stores.
Living the same sequence right now. 9" rear brakes on my OT '69 SCJ Mustang. For once I did have some foresight, this time instead of playing Russian roulette with RockAuto offering up the wrong items for my car, I pulled the wheel cylinders apart and measured the bore size. In my case 7/8" WC bore got me the right wheel cylinders (but the wrong axle bearing flange gaskets.) Why the Rock Auto site asks you for the year/make/model/engine then offers you up parts that did not come on that vehicle is a @#$%&+ %@$#&+. I haven't done the JetNow1 swap return, but since their friggin' system is the problem, it's tempting. And yes, the brakes are entirely different (backing plates, shoes, wc bore) by engine size. My factory 31 spline big bearing 9" is just enough different to be a problem. God forbid they'd have some parts uniformity.
Yep. Somebody posted that the Mustang line changed components based on paint color. HA! LOL!! Seems that way with lots of years.
Those bastards sent me two of the same side wheel cylinders with two different part numbers (a 10" and a 11") on my last bronco rear rebuild, they could've looked at the order and seen I was ordering everything for both sides with 10 inch brakes ! They wouldn't return it because they said it was more to ship than the part cost. The year of the rear also makes a difference in what parts it has, it's not all divided by big bearing and small bearing. The 74-75 "medium duty" rear is the odd ball and also the one that is problematic on parts, it's a small bearing with big bearing spacing backing plates. The 66-73 and the 76-77 are the easy ones to find the right parts for. Here's a couple wheel cylinder boxes you can check and a bag that I believe contained a 74 wheel cylinder or it could be a spring kit bag, I have 3 of these rears in use so all the parts are mixed together in one container of left overs, I couldn't find that new wheel cylinder they wouldn't take back but I'm sure it's out there somewhere.
I had an 8" that had two different wheel cylinders listed. Had to be sure I ordered the correct one. For 9" expertise, why not call Currie Enterprises? https://www.currieenterprises.com/?...EFllnDGz-EDBuhwTR3udqLWPJib7REecaAgVbEALw_wcB
Check out Jeff's Bronco Graveyard, he has the parts and he knows those old Broncos and 9 inchers. He helped me with my drums, wheel cylinders and rebuild parts Early Ford Bronco and Truck Restoration Parts - Jeff's Bronco Graveyard
The Bronco Graveyard is pricey, I saved over $100 bucks by ordering the same stuff individually from Rock Auto and a couple pieces locally. He does have the stuff if you don't want to search it out yourself. The one thing I never could find from any supplier was the 74-75 backing plate gasket, none of the 3 offered sizes would fit that goofy "medium duty" rear, small center hole but large bolt spread.
I ran into this once years ago , as best as I can recall . The small bearing WC is the same as 8 in rear in a Mustang . But again this was 30 plus years ago . Bronco Graveyard is your friend here
What year is the rear end, like I said different years, just like 10 inch vs. 11 inch, take different pieces ? Above it was mentioned that they should be 15/16 bore but some were only 13/16, need to know specifically the year, the drum size and if it was 6 cyl or 8 cyl.
The rear end in the coupe I’m building is a 66 Bronco small bearing with 10” brakes. The wheel cylinders that were on it were 1.17” which seemed big. They were really rusty. I ordered from Rock Auto listed as either 13/16” or 27/32” which is about the same as the 10” brakes on the Maverick rear in my 31 pickup so it should work fine. I ran those on the pickup with 40 brakes on the front with no issue. I also ordered self adjusters for a later year Ford with 10” brakes and retro fitted them. The 66 Bronco rear must not of had self adjusters as the adjustment hole is in the wrong place on the passenger side backing plate. Looking in the manual for non adjuster brakes, it looks to use the same adjuster on both sides so one side is flipped. Sent from my iPhone using The H.A.M.B. mobile app
Don’t know year, engine, or much else. No tag on center section. Just bare backing plates. 2-1/4 shoes and drums fit it. Searching some Bronco sites, the rear ends were seemingly a smorgasbord of various parts, and 74-75 were unique in their own. Should have gone in another direction, or found a complete one.
Did you look up those part numbers off those boxes I posted the photos of ? There should be some measurements in the specs to go by to see if they'll fit your backing plate, there should also be a part number stamped into the backing plate to use to look up so you can figure out what you have.
66-73 is definitely different than 74-75 Just two copper coins, but the $100 saved is gone now. I have dealt with bronco graveyard many times on non H.A.M.B. Gen 1 Broncos. Knowledge has value. Sent from my iPhone using The H.A.M.B. mobile app
As a early bronco nut some more information is needed to get the correct wheel cylinders. I have no Idea but ford used a few different wheel cylinders along with backspacing backing plates . This changed the brake pad width. So you can have a 6 cylinder with a 10 inch drum thats 1 1/2 wide or could be 2 inch. They did this and can be really confusing as my 1968 bronco has 10 inch drums 2 inch wide my 66 has 10 drums 1 1/2 option was 11 inch. Do you have the drums ? And did you put this rearend together drums and backing plates original? Also early bronco where single master cylinders jelly jars . Do you know what year the rearend is? 1966-early 68 had jellyjars and then 1968 to 1975ish had a different master for manual depending on your brake option it could have use the 1974 to 1977 power brake option forgot what year they started Power . I have ordered cylinders for my 68 and its a 50/50 to get the correct ones for the auto parts stores . I was told this is the only one listed wrong and the reason Jeffs bronco grave yard is super knowledgeable. I use Toms bronco parts or bronco
When it comes to things like this I really miss parts stores that had a retired mechanic behind the counter. The guy that knew the books. He would go right to the brake parts picture book and give you the right part after you realized you had a problem.
Thanks for the info. I am familiar with Tom’s, the Graveyard and others as I have one of these Gen-1 Bronc’s myself. Time for some phone calls. If I had ANY idea that these rears were prone to such a combination of parts, I certainly would have gone a different route. Lesson learned! Thanks, I did. Already had the backing plates PC’d so the number is gone. NAPA # is 13/16 iD and looks like it has the 1-1/2” locating index. I’ll look at them. Delco # only showed a pic, no specs, but it looks like the smaller index.
This is the 74 I recently rebuilt, that's in my 57 Chevy p/u, with parts from Rock Auto and a couple local parts stores, it was kinda like yours with only one of the wheel cylinders left under the drums, everything else was missing. Once you figure out what you need it'll be like any other brake rebuild, these are great rear ends for it's narrow width and strength, worth a little aggravation at first. I changed the bolt pattern to 5x4.75, the reason for the extra bolt pattern on the drum. That Delco box was for this one
Just in case, you haven't changed it, the cable eye is supposed to be under the return spring; as it is in the picture posted by @swade41 .
The old Wagner manual I have showed it above. Although looking at it, it would align better underneath. Easy enough to change. Sent from my iPhone using The H.A.M.B. mobile app
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