Modern Delphi TLS wheel cylinders not fitting back plate?

[Michael7]

We have recently sold genuine Delphi LW11549(GWC102) and LW12051(GWC103) small-bore front twin-leading-shoe wheel cylinders that do not line up properly with the backing plate holes. Once the rectangular boss of the cylinder is pushed into the back plate, the cylinder holes are partly covered by the backplate, preventing the screws from passing through. Either the screw holes are in the wrong place on the cylinders, or the rectangular locating boss is incorrectly located and pushes the cylinder screw holes out of alignment with the back plate.

Has anyone else run into this?

I realize it only requires a minor enlargement of the backplate holes to allow them to fit, but customers who receive a product that does not fit are wary of modifying a standard original part to make a modern replacement part fit.

I also realize the customers may unknowingly no longer have the original backplates that accepted the early wheel cylinders, and it is possible that later backplates may not align properly with early wheel cylinders.

Any info welcome. Thanks.

[mk1]

There was a thread on this a while ago, in that thread the problem seemed to effect very early back plates only.

I am sure that as the Mini gets further & further away from production there will be more issues of this type to come.

[Michael7]

The other thread was about rear wheel cylinders on early back plates, so not directly relevant to what I'm trying to determine, which is the accuracy of current production early front twin-leading-shoe cylinders.

[nick rogers]

Mike, Your second Lockheed number refers to the later 15/16" cylinder, but assuming you mean LW11550, these will be out of line as you describe, when fitted to later TLS backplates. The first time we upgraded a 64 TLS car to bigger cylinders we discovered, as you have, that the holes do not line up and you need to elongate very slightly.
I can usually supply original Lockheed boxed 4241-550 and 4241-549 as well as the later 4241-050 and 4241-051 if you ever want originality. Unfortunately these tend to be more expensive than more recent replacements.

[Michael7]

Hi Nick,

Yeah, I now see I got the GWC103 Lockheed part number messed up, it should be LW11550 as you say. A good friend over there pointed out to me that when Lockheed designed the later wheel cylinders, they probably made the later back plates intentionally different so that during the transition from early 13/16" cylinders to later 15/16" ones, the back plates would only accept the correct wheel cylinders to avoid accidental mixing of early and late cylinders on the same car. Of course enthusiasts found it was very easy to modify the early plates to accept the later cylinders and thus gain the better brakes.

In the case of our 2 customers who could not fit the current version of the early cylinders to their backplates, both unknowingly had later backplates than what would have been the original ones for their cars. We have now tested the current Delphi early cylinders on the early 112906/7 back plates and they do fit correctly. These days, it is unsurprising to find that early cars have non-original components fitted and the owners are oblivious, which makes supplying the correct parts difficult.

Mike