WTF, my brake pad fell out, ***happened again, cressida PROS wanted***

[Mos]

From memory the JZX81 discs are a larger size then the MX83 stock discs, and therefore the caliper bracket has longer mounting lugs than the MX83 caliper.

From memory the diameter is the same but the thickness is noticeably larger (but haven't measured it), so it's feasible they are JZX81 calipers on MX83 discs (unless the discs are heavily worn 20mm inside a 22mm caliper but they don't look *that* worn as the disc should be centered in the bracket).

The part of the bracket which you picture there does not necessarily need to be centered

Yeah it does need to be centered - the bracket is fixed relative to the disc plane and holds the pads the place. The caliper only squeezes the pads, it doesn't stop them from rotating with the disc. The gap between the bracket and the disc should be SFA, certainly a lot smaller than the thickness of the pad backing plate, let alone a 60% pad. A pad with 0.5mm of lining shouldn't come anywhere near falling out.

as the caliper mounts off the rubber booted lugs at the right of the picture, making it offset to the right (back of disc) and therefore centered.

Yep, but the caliper movement only adjusts to the wear of the pads and doesn't do anything in terms of placement of the pads around the circumference of the disc - IE caliper doesn't stop the pads from rotating along with the disc - the bracket does that job.

MR DOHC, after you've done what GT suggested, and found the disc to be either 20 or 22 mm (or close enough to it) then you almost certainly have the wrong calipers for the discs. To be more certain, you would need to measure the gap of a standard MX83 bracket (whether the 20 or 22mm), and/or find out the thickness of a JZX81 disc.

The JZX81 disc also has vents coming out at the inner circumference of the friction area, against the hub, whereas the MX83 disc does not.

Mos.

[gianttomato]

MR DOHC, after you've done what GT suggested, and found the disc to be either 20 or 22 mm (or close enough to it) then you almost certainly have the wrong calipers for the discs. To be more certain, you would need to measure the gap of a standard MX83 bracket (whether the 20 or 22mm), and/or find out the thickness of a JZX81 disc.

This is what I suspect - there must be some sort of mismatch. It is just very easy to measure up the rotor seeing as it is there on the car already. Whilst it is important to see what the thickness is (the reason I specify either 20 or 22mm is because there are two different specs for the MX83), you also need to check the rotor height, which for both types of MX83 rotors is 68mm. You may just have 20mm thick rotors where you should be using 22 mm ones - this would give you the 2mm outboard shortfall that is causing you grief. I have no idea what the JZX81 rotor height is but maybe you could get someone to check it for you or track some down from a halfcut.

If it's all too hard, just do the BA Falcon rotor - Nissan 4 spot caliper conversion and be done with.

[allencr]

Quote:
Originally Posted by allencr
I don't know what you've got, but I've never seen any design
that was totally dependent on the anti-squeel/rattle shims/clips to retain the pad. They usually are 'extras' only and aren't there to 'push the pad away from the rotor when not being applied'.
I think you've got another problem - wrong pads or wrong caliper & bracket. They should never be able to drop out unless worn out completly, plus a VERY worn disk.



i dont have problem, the previous person to install the pads was a cock head, all fixed now

.

That's 'Mister Cock Head' to you!

[Mr DOHC]

i have a 280mm rotor, 68 mm height and 22m thick, does this mean anything to anyone, the JZX81 rotors are 280mm,

but that wont make it be centered anymore, as the thickness and height are the same as the cressida, so that wouldnt change the centering of it would it??

should i maybe put a spacer under each rotor to the hub by the amount needed to bring it out some more

[RT104GT]

i was on my way home from the drags theother night{numerour my brake pedal hit the floor, no brakes.
can be very catastrophic.

pics to follow

A shades of Mt Tomah 1974 in my 1600S fitted with an 8RB engine.

Brake pad moved forward under decelaration round all those bends going down the line of Bell Road.
And we just went out into space and ended up in a tree, did not even try to take the next fast outside sweeper.
The pad moved forward even further and the brake pedal was hard as a rock and the car did a right VIFF and OFF WE WENT.

Car was totalled FULL back ROLL CAGE SAVED OUR LIVES. )

I broke two scapula and fractured my skull, could not drive for three months.
Both arms in a sling.




The only remains of my 1967 Corona 1600S 8RB powered. SOB!

Routine maintenance lads.
You might catch it if you are lucky.
QED.

[thechuckster]

i have a 280mm rotor, 68 mm height and 22m thick, does this mean anything to anyone, the JZX81 rotors are 280mm,

but that wont make it be centered anymore, as the thickness and height are the same as the cressida, so that wouldnt change the centering of it would it??

should i maybe put a spacer under each rotor to the hub by the amount needed to bring it out some more

using washers to space the disk are a bad thing ok...

you need to find a disk that fixes this 68 mm height figure or confirm that the calipers are JZX81 items.

[takai]

Lots of stuff by Mos

Fair enough, my memory of the sliding caliper system on the MX83 is hazy at best.
MrDOHC: this is what you need:

No more pad falling out again.

[gianttomato]

Er hem....Takai...

If it's all too hard, just do the BA Falcon rotor - Nissan 4 spot caliper conversion and be done with.

[YLD-16L]

If you want to work out what diameter and thickness rotor that caliper is designed for it is stamped on the caliper body and slide bracket of almost all toyota single and twin piston calipers.

You will find L and R stamped for left and right a 2 digit number on the fixed section of the caliper (the part that is bolted to the strut) that indicates the disc thickness it was designed for and a 2 digit number on the fixed part and the body containing the piston which indicates the width disc they were designed for and another 2 digit number indicating the piston diameter in mm.

I think that caliper is designed for a disc with a thickness of 30mm (as stamped in that pic).

EDIT: disc diameter was not stamped, only L R/piston diameter/disc thickness.

[takai]

Er hem....Takai...

Ooops, missed that bit.

[Mr DOHC]

i have spaced it out 3.2mm and it sits almost center, i will get a 4.0mm spacer milled up at work to have it perfect

[gianttomato]

That's wonderful.

Have you eliminated the possibility that when the pads are really worn down, they might now fall out from either side?

Just asking the question that needs to be asked. Perhaps you should take heed of your current sig.

[YLD-16L]

I was about to echo the sentiments GT noted above. Excellent that the disc is centered but it doesn't change the fact it is approximately 8mm narrower than the caliper is designed for.

Here are some pics so people can identify what the stamping on their Toyota calipers represent and hopefully avoid the dangerous situation that has occurred in this thread.

This is a dismantled st185 Group A GT4 caliper ready for cleaning/painting/rebuild.



The fixed bracket has a clear identification on it for the thickness of the disc which it is designed to be used with, in this case it is designed for a 25mm thick disc.



You will notice in this pic it is clearly identified as a Toyota caliper, the "R" signifies it is the right hand caliper, the 57 indicates it uses a 57mm diameter piston and again the 25 means it is designed for a 25mm thickness disc.



Here is the piston, clearly marked as a 57mm diameter piston:



This is typical of most Toyota calipers of single and twin piston design, so no excuses now for using the incorrect thickness disc