Author Topic: E 29 Brake Plates  (Read 1553 times)

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Offline TonyC

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E 29 Brake Plates
« on: 02 Nov 2017 at 13:27 »
Hi All,

I am making a pattern to enable me to produce a replica casting for the front brake on my E29. As you can see from the images attached mine is a bit worse for wear!.
The pattern I am producing will incorporate the lugs that are on the front brake as well as the ones on the back one, along with the ribs for holding the springs in place. The original was a die cast part with change pieces in the mould to produce the different parts.

Do any of you learned forum members know of any other model of  Douglas motorcycles that these can be used on, or if any further mods can be made to the pattern to produce further types of brake plate

Regards Tony
« Last Edit: 02 Nov 2017 at 14:14 by TonyC »

Offline eddie

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Re: E 29 Brake Plates
« Reply #1 on: 02 Nov 2017 at 14:25 »
         The Douglas 'servo brake' was used right up to 1938. The later ('33? onwards) brakeplates for use with cast iron drums had a lip on the outside in an attempt to keep the weather out of the drum.


Offline Doug

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Re: E 29 Brake Plates
« Reply #2 on: 02 Nov 2017 at 19:03 »

I would have thought that backing plate was used starting with the 600EW in 1927. What you have looks identical (less corrosion!) to my F28, so add E/F28 to the list. Then your E29, so figure F29 as well.

The E/F28 part number for the backing plate is 8145-5; the suffix seems to indicate revision five. Same part number front or rear. The part number for the OC backing plate is also 8145-5, so the backing plate is same for it. I strongly suspect the 1925-27 IoM model also used the same backing plate, but don't know how many customers you would get for that!

However, the revision seems to be linked to a change in the depth of the cup to hold the felt. Earlier it was about 7/8 of an inch deep inside and later it became an 1-1/8. My F28 has the 7/8 deep pockets.

The 350EW uses part number 7380-3, superseded by 7873-5. Dimensionally I cannot see anything different between it and 8145-5 except for the axle size. The one I have for my 350EW project does not show evidence of the die cast inserts. Either it was early on before the joints in the die insert wore or early on they sand cast them; and it does appear to be a sand casting. It has the 1-/18 deep felt seal pocket. Or I think it is 350EW, it has the correct hub and bastard rim size. It is stoved-in on the face and I am missing a backing plate for the front, so I might be a future customer!

The T6/S5/S6 used part number 9833-2, and that does not seem different from the previous other than the adjuster bosses have moved and it is back to a 7/8 deep pocket.

At some point the face of the backing plate did change. While it still does not have the lip that wraps over the rim of the brake drum, the face does have a bulge/shallow cone that increases the wall thickness as you move inward to the axle. So that would mean a different pattern. Though it would only mean a different pattern for one face, so you still might be able to get more bang for your buck by swapping out one half of the pattern. This version is likely shared in common with the A31 and derivatives, certainly the F/G31 models (part number 12842), and I think continued on with the cheaper lightweights even after the flanged version of the backing plate was introduced.

F28 backing plate

EW backing plate


[corrections.  02Nov17 -Doug]
« Last Edit: 02 Nov 2017 at 19:37 by Doug »