Can you ID these calipers?

[citjet]

I just pulled these calipers off the rear of my 72 240z, the PO had said that he had accomplished the rear disc conversion with Toyota 4x4 calipers. I have searched several sites and have not found any Toyota calipers for the conversion that look like these. Is anyone familiar with this unit? The pads are not too bad now, but I will eventually need to know what these came off of to get replacements.

Would this be a good time to upgrade to the 4 piston calipers or should I stick with what is working? The parking brake doesn't function correctly and I am trying to see what I can do about it, it only barely holds when the handle is pulled all the way up. I have no more adjustment left in the cable to pull tighter, but it appears as though it wouldn't matter anyway as the springs on the caliper are compressed all the way anyway. Is there an additional parking brake adjustment that can be made on the caliper?

Thanks in advance

[carguyinok]

Just a thought here. Do the pads have any numbers on them? You could cross those numbers over at the parts store and know what you have.

Or maybe a part number on the calipers?

[citjet]

The calipers are too dirty to find anything on right now. I will be cleaning them up today and will look to see what I can find in the way of part numbers.

[citjet]

The PO REALLY liked silver paint and coated everything with it, calipers, engine block, etc. It makes it tough to see anything until you strip it off. If I decide to reuse these I will be cleaning them up and coating them with POR-15.

[Arne]

Those look like rear calipers from an early Maxima, or something similar. A very common rear disc conversion part.

The Toyota 4x4 calipers are used on the front to give four piston front brakes, rather than the stock two piston units from a normal Z.

[citjet]

Thanks Arne, that makes more sense now. The front calipers are four piston units, I guess he was just confused between the front and rear conversions.

[jmortensen]

Those are 79-81 280ZX rear calipers (and probably come on the Maxima from the same years too). I ran those on a bracket from Z-Quip for years. They're a reliable caliper but the pads are tiny and I had a hard time getting the brake bias dialed in when using 4x4 front calipers. I was able to dial it in when I used stock front calipers with those rears.

[citjet]

Those are 79-81 280ZX rear calipers (and probably come on the Maxima from the same years too). I ran those on a bracket from Z-Quip for years. They're a reliable caliper but the pads are tiny and I had a hard time getting the brake bias dialed in when using 4x4 front calipers. I was able to dial it in when I used stock front calipers with those rears.

Funny you should say that, this was the reason why I pulled them off to begin with. I thought I had some blockage somewhere in one of the lines that was causing the jerkiness. I found that I had very little pedal travel and the brakes were extremely sensitive and grabby when applied. You could press fully on the pedal and the brakes would grab but never enough to lock up, if you needed to stop quickly you would just stomp down and hope for the best.

I broke all the lines loose and put low pressure air through each of them with no apparent blockage. Did you have this problem with them when you were running them? What about the parking brake?

[240znz]

You need a larger master brake cylinder as you are pushing more fluid with the larger pots.

If you have access to the stock drums, it might be easier to convert it back as rear brakes are there really only to stop the rear from drifting. Unless you are all out racing, not sure if the conversion is worth it in the first place.

[JonnyRock]

Rear drums may not be cool, but they're more than adequate for all but hardcore track time in the Z.

I'm with 240znz, switch back.

[jmortensen]

Funny you should say that, this was the reason why I pulled them off to begin with. I thought I had some blockage somewhere in one of the lines that was causing the jerkiness. I found that I had very little pedal travel and the brakes were extremely sensitive and grabby when applied. You could press fully on the pedal and the brakes would grab but never enough to lock up, if you needed to stop quickly you would just stomp down and hope for the best.

I broke all the lines loose and put low pressure air through each of them with no apparent blockage. Did you have this problem with them when you were running them? What about the parking brake?

Mine were not jerky and they weren't overly sensitive either. They worked fine, they just didn't work enough. Parking brake was pretty easy to adapt: I used a ebrake cable from a late 80's 240SX which hooks straight up to the caliper no problem. Then on the front end of the cable I removed the rear bell crank and attached the cable directly to the handle. Worked fine like that, and I had it adjusted to about 3 clicks. I really liked that brake setup for the parking brake.

As to switching back to drums, I wouldn't. I'd either keep what you have or upgrade to a better disc setup (there are many options). I hate working on drums, especially on a Z where the aluminum drum has corroded to the stub axle so bad the damn thing is practically welded on... I had enough of that!!!

EDIT--Re-read your post and if you can't lock up the wheels at all, I'd guess you have a bad booster. You should be able to lock up the fronts at least, but the bias problem will leave the rears doing relatively little in comparison to the fronts. When I had the Toy fronts and ZX rear I did a driving school. One of the things they did was have us drive through a big puddle and slam on the brakes just to get the feel of locking them up. I was told by my instructor that my fronts locked but the rears didn't.

Edited March 2, 2009 by jmortensen

[citjet]

I'm planning on keeping these discs in the back for now due to budgetary constraints. I just read in another post that the MC outputs changed sides from front to rear between the 240's and the 280's. I believe that the PO had switched over to a 280 MC and I have not checked to see if the larger cylinder is indeed going to the front brakes, I assume this could be part of the problem and will checking this next.