240 vs 280 drums. Differences?

[jmortensen]

I haven't been into Z drums in a long time, but my brother-in-law is trying to sort his car out. He has a 240 and he needs new wheel cylinders. IIRC the 240 has one piston in the wheel cylinder and the 280 has two pistons. Also it seems that the 280 wheel cylinder is about 1/2 the cost of the 240 wheel cylinder. So can the 280 cylinder just plug right in? Are there other differences in the brake shoes or spring arrangements that need to be modified or changed? I think the front calipers are identical so I wouldn't anticipate any changes in brake bias or any of that...

[Arne]

You'd have to replace the backing plates, return and hold-down hardware too.

[chickenwafer]

Whoa! Jim with a question! This is going in my dairy!!!

Just joshing, Jim. But I believe they don't bolt right on- some custom modification might need to be done. But try it out and see if it works and let us know.

Dave

[jmortensen]

All I can say is it's a good thing I'm not lactose intolerant.

[jmortensen]

Seems to be unanimous about the backing plates. Thanks. I'll tell him to buy the 240 wheel cylinders.

Jon

[montoya_fan01]

I don't believe the backing plates are the problem, but the hard lines from the individual brake hoses to the wheel cylinders are different. The location of the fittings on the wheel cylinders is different, so the 240Z hard lines won't line up with 280Z cylinders.

[chickenwafer]

oh crap I spelled diary wrong.

[mdbrandy]

I don't believe the backing plates are the problem, but the hard lines from the individual brake hoses to the wheel cylinders are different. The location of the fittings on the wheel cylinders is different, so the 240Z hard lines won't line up with 280Z cylinders.

OK. the backing plates are definately different. The spring setup is different. The 240 cylinders "clip" to the backing plate in a sliding setup, where the late 280 cylinders have 2 bolts that bolt them to the backing plate. A late 280 cylinder will definately not work on a 240 backing plate.

Now, having said all that, I'm going off my early 240 versus a late 280. If memory serves, late 240 and early 280 setups may be the same. But the cheap cylinders are the late 280 ones.

[montoya_fan01]

I looked through my stack of spare parts and it appears that the rear cylinders for 70-76 mount the same way, and then 77-78 mount differently. In my earlier post, I may not have conveyed what i meant very well, but my point was that the hard lines of a 70-72, or those from a 73-76 Zcar will not be compatible with 77-78 280 cylinders even if the backing plates were the same. You need hard lines to match the cylinders you intend to use. My spare 280Z backing plates must be from a 75-76 because they are identical to the ones on my 240.