Jump to content

IGNORED

240Z/240K rear brake drums interchangeable?


Alfadog

Recommended Posts

I have a pair of rear brake drums that came spare with my 240Z when I bought it, but were lost in the deep dark cave known as the "garage" some time ago. I found them again the other day and thought why not swap them into the 240K? They look fairly identical except the Z has heatsink shims around the drum.

Before I go ahead and do it, is it ok??? I don't see how it could be a problem, but I thought I better ask.

Here are some pictures. Both are marked with MAX. DIA. 230.0MM, 9.055 as shown in the second image.

post-1243-14150796858494_thumb.jpg

post-1243-1415079685881_thumb.jpg

Link to comment
Share on other sites


It's a popular upgrade for the 510/Bluebird and Skylines of the era. I would get them checked for warpage, though. I had a set and the mechanic said they were warped so I couldn't use them. The finned aluminum is supposed to dissapate heat better than the cast iron.

Link to comment
Share on other sites

I know when putting them on the 1600 you have to grind off the outer lip of the backing plate to make then fit right down, or get the fins machined off the bottom 3mm of the drum to fit. I would suspect that the 240K would have more in common with a 1600 rear end than a Z. So yes they are the same size, but may require some trimming down.

Link to comment
Share on other sites

Right on. I didn't notice that when I test fitted them :stupid:

Anyway, I've got them on now and they look nice (as nice as drums can look), but they don't work/b]. I don't know what I did wrong... The handbrake doesn't work and I can tell through the foot brake that they don't work too... When I pulled back into the driveway I gave it a BIT more pressure and the rear (right?) went something a little like "CLONK!"

I have to admit, I did apply the footbrake while the rear right was off. Could this have done something?

I'm so not cut out to be a mechanic :(

Link to comment
Share on other sites

Sounds like you probably blew the wheel cylinder out. Time for a rebuild. When you applied pressure without the drum on there was nothing to keep the brake shoes from expanding more than normal causing the pressure to push the pistons in the wheel cylinders out and "blowing" off the rubber caps. If your lucky you didn't rip the rubber caps and maybe able to reuse them. However, I would probably rebuild them both for safety's sake.

Link to comment
Share on other sites

Great. Looks like I need to get a loan. :cry:

It sounds alot worse than it is unless you are driving the car with it that way. It is a pretty simple task to do. Go buy a wheel cylinder rebuild kit for each rear wheel and brake fluid. Watch how you take it apart. Clean everything real good. Put the new parts on. Repeat for other side. Bleed the brakes. I may have missed a step or two but it really is pretty easy. Good luck. Gotta love these old cars!!!

Link to comment
Share on other sites

I have to admit, I did apply the footbrake while the rear right was off. Could this have done something?

You drove the car with only one drum on? Or was it parked and you stepped on the brake and one drum was off? I think David's right, you popped the wheel cylinder.

I'm so not cut out to be a mechanic :(

No, you just need more practice . . . .

Link to comment
Share on other sites

Haha don't worry Lachlan - we've all made mistakes - some more expensive than others.

At least you're having a go - that's more than I can say about many people out there.

Considering the age of the car, it might be worth pricing new wheel cylinders. If they're really cheap, probably best to go that way, rather than try to rebuild the old ones.

They will be a ba$tard to replace (nothing too difficult - just a pain in the rear) but nothing's impossible. There are a series of interlocking shims that hold the assembly in place (on the back side of the backing plate) that are very fiddly to fit. Just make sure you note the order they come off, and make sure everything's clean, and it should be fairly straight forward (making sure you don't bend them in the process).

Link to comment
Share on other sites

You only need half the shims they supply you with to get them to hold on too :). Its not difficult but make sure you invest in a flare wrench (ring spanner with a side missing) for the 10mm brake line nuts. Round one or four of them off and life starts to suck that little bit more.

Chris

Link to comment
Share on other sites

OK so the wheel cylinders are NLA from Repco/CheapAutoSpares. Going to have to have them resleeved instead.

So in the mean time, here are some photos. Not particularly exciting but I like to document everything.

1. Appearance with stock drums

2. Stock setup

3. Backing plate bent back, sanded and painted

4. S30 finned drums on

5. Appearance with S30 finned drums

post-1243-14150796873569_thumb.jpg

post-1243-14150796873922_thumb.jpg

post-1243-14150796898703_thumb.jpg

post-1243-14150796899022_thumb.jpg

post-1243-14150796899322_thumb.jpg

Link to comment
Share on other sites

I would be inclined to ring PBR for new cylinders before going the resleeve option. Surely they must be available somewhere, failing that whack a set of ZX discs on the back and be done with it :). Happy brake work, and make sure you dont get any of that fluid on your nice shiny paintwork ;).

Chris

Link to comment
Share on other sites

The old guy at Cheapa Auto Spares looked in the new (PBR) catalogue and couldn't find it, then looked in an old book that had it, but after comparing to new book saw that it was no longer available?! I thought it was strange too, but usually they're pretty good with this kind of thing. Repco had one for a 1600 but that's it... I probably could have got some eventually but I'm pretty sick of this. It started out as just something to do one afternoon when I was bored. :ermm:

Anyway, they are at a resleeving shop now being rekitted so I'll have them back by tomorrow. Hopefully they'll go in as easily as they came out - and hopefully it all WORKS.

After seeing how it all works, I'm curious (oh God not again). Why is brake fluid such a nasty nasty liquid? Like, why does it have to be used instead of anything else? Potentially stupid question........

Link to comment
Share on other sites

Seems odd, but I guess there isnt a demand for them that much at the moment. I have a damn resleeved cylinder on the landrover, which since resleeved has always stuck when left for a week or so without being used, might have just been done poorly, admittedly it does come unstuck after a few heavy applications, but until then it throws the car horrendously off balance and spears it across the road ROFL .

Brake fluid has to be pretty good at what it does, it has to have a super high boiling point, because when it boils your brakes are no more, it shouldnt absorb water too much (But it does and should be changed yearly or so), it has to maintain dimensions as the temp changes because if not as the wheel cylinder heats up on braking it will increase pressure and lock a wheel. It also cant be allowed to freeze (not an issue where you are). And has to be non damaging to the braking system. I think that new silicone brake fluid will not damage paint, but if used in an old braking system (any old parts) something will react and seize up everything.

Oh the joys of brakes, thats what the manual box is for ;)

Link to comment
Share on other sites

OK, so I got the wheel cylinders resleeved and I managed to install everything back together. Now trying to bleed the brake lines...... but they won't bleed! Dad pumps the pedal, I let the fluid go from the bleeder. Did so until a steady stream spurted out. Did both sides... Used quite a lot of brake fluid in doing so... but the pedal is still spongey. Pump it a few times and it's good, but becomes spongey again very quickly. I can't believe the lines are STILL not bled properly... could it be anything else?

If only life had an undo button. :(

Link to comment
Share on other sites

What's the exact process you used for bleeding the brakes?

I always get the helper to give it a couple of pumps and hold pressure. Then I crack the bleed nipple (enough to let the fluid run out, yet maintain good pressure in the lines), and let it drain. Before the pedal gets tot he floor, I tighten the nippple again, so that it can't suck air back through the bleed nipple. It is very important to keep pressure in the brake lines, so that you can't suck air back in. Did you do that? Also, make sure the fluid reservoir is always topped up, so it can't suck any air in.

Another method I recently heard was to use a large syringe with a rubber hose, and suck the old fluid out through the nipple. Again, keep the fluid topped up in the reservoir. I have never tried this method, so can't comment on it, but it sounds logical.

If you've properly bled the brakes, then your back drum shoes probably need adjustment (the new drums may be slightly more worn than the old ones). The back brakes aren't self adjusting, so no matter how much you bleed the brakes, they will always feel spongy.

You'll see the adjuster in your picture where the drum is off, at the top of the assembly, where the tops of the brake shoes pivot. This has bolt coming from the back, which has a tapered head on it (between the 2 pistons that locate the upper ends of the brake shoes). This can be screwed in or out to adjust the brake shoes (although it's best to remove all load from it before trying to adjust it, as it will probably be very tight and rusty).

This could be the problem.

Link to comment
Share on other sites

Did you bleed all the brakes and not just the back ones?

Are the cylinders in properly? It may sound stupid, but a friend of mine had a similar problem with his VW. Tried everything and still had spongy brakes. Another friend helping out noticed that the cylinders were upside-down. That made it impossible for them to bleed the air out because the nipple was at the bottom.

I use the "glass jar and tube method." I fill a glass jar with clean fluid - about an inch or so. Then I slip one end of a length of tubing onto the bleeder nipple and the other end into the glass jar. I crack the nipple a bit then step on the brake pedal or sometimes push with my hand. When it stops bubbling, I close the nipple and move on to the next one. The fluid in the jar keeps air from entering the system while allowing air to be pushed out. It's also convenient when you don't have a helper handy.

Link to comment
Share on other sites

lachlan,

I managed to buy a set of new cylinders from repco in August 2004. they were from memory very cheap at around $30 each..

I have a set off my project car if you want them? not sure what state they are in but they are intact! :)

did you bleed all the wheels, closest to furthest?

Link to comment
Share on other sites

I thought the front and rears were on different lines? There are two fluid cylinders..? We only bled the rears. The fronts need it too?

Thanks for the offer Kent, but it's too late now! The reconditioned ones should work fine (at $40 each no less LOL). I had some on the parts car too but thought new/reconditioned ones were probably a wiser choice. The cylinders won't fit upside down so that's good.

Thanks guys for the advice. Will have another go when I can...

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.