MTFCA Forum

I had a set of 09-25 RMB around and I am setting out to put them on my speedster that has a 26-27 rear. When I bolt the casting on top of the radius rod it pulls away from the backing plate due to interference between the casting and the radius rod. Is the 26-27 setup different in what ways? I can grind the casting away but it’s probably not the best idea. Thanks

John

The 26/27 RM used the original brake drum and up to 1925 had an added on brake drum that is a different size then the 26/27 stock one. You can't mix and match, the castings are different as are the backing plates and their mounting/fitment locations between them and the RM brake bands. My suggestion would be to post an ad to swap them for the correct year for your rear end or use your original lined shoes and this;
https://www.snydersantiqueauto.com/Prod ... l-t/brakes
Then sell the 25 back set. It would be a plus if you have the drums that came with the kit.

Makes perfect sense! Appreciate the quick help as I thought I was messing something up.

The setup came to me for free so I’ll make the calls on Monday to get setup

IMO, think the reproduction R-M brake castings are the same, but there are Left and Rights. Think that subtle changes in factory '26-'27 radius rods can be the issue. These Improved Car rods are different than earlier.

On my R-M install, had to grind a small area where the casting was impinging on the radius rod yoke. That let the casting sit flush. Easy fix.

Nothing is the same. The drums are a different size so the mounting is also a different size. The bands are a different size. You should be able to sell them to a club member who wants the brakes on his car and buy a set to fit your rear end, or you could buy an earlier housing and install the innards to the rear axle in the earlier housing so your brakes would work. That would probably cost you less if you have all the parts for the Rocky Mountain brakes including the drums.
Norm

When the guru of drawings made the repro R-M brakes drawing, there is only one yoke casting, so these castings are same for small or large


http://www.mtfca.com/discus/messages/50 ... 1437393203

I’m having a similar problem on a customers 26/7 Ruckstell axle. I called Bud and he told me the drums, the linings and the mountings are all different between the two designs.

As Norman explained nothing is the same. The current Rocky Mountain brakes were copied from an original 1926 AC brake, and are not even close to a correct Rocky Mountain Brake!

Tony

Thanks for clarification on the parts differences, figured the castings were same, but are not. Was wrong on that account

This is the '26-'27 casting for mounting over the radius rod , you can see the "R-M" logo extends to the curved end of the casting. This is the one side that needed clearance over the radius rod, to allow it to fit flush. Simple work, likely the fit was too tight due to the casting 'draft' that occurs when you cast parts, you need the part to remove from the mold, so an overhand is on most edges due to this draft.

'26-'27 repro R-M


Here is the casting for the '09-'25 repro R-M brakes, it is more circular and has the 'R-M" logo at the top of the casting frame.

'09-'25 repro R-M brakes


Larry

Know you like original Rocky Mnt. but not all can find good old used sets. So my experiences with both the small axle and large '26'27 axle repro R-M brakes mfg by Rocky Mountain is just fine, I like 'em.

They stop my Fords fine. Won't leave the garage without 'em!

If Jack would have done his homework when he started making the brakes, he would have found the brake pedal bracket and the equalizer. Instead he found a Bennett equalizer which is backward from a Rocky Mountain. Rocky Mountains use a cable, and pull on the brakes. Having to use rods just complicates the process, and adds extra weight and parts which are really not necessary.

When using the currently produced Rocky Mountain brakes,they work very well going forward, however tend to loosen when going backward. They work like an oil filter wrench, they are actually assisted by the forward movement of the drum.

The above being said, be sure to have the internal transmission brake in place and adjusted so that when you push hard on the pedal it will tighten the transmission brake. This will hold you when going backward.

The parking brake should also operate one click before it activates the rocky mountain brake. This will stop you when rolling backward in case you have a drive train failure.

Norm