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The mkiv Supra Owners Club

Refurbing J-Spec Brakes


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After Digsy's help I thought I would take a few piccies

 

Parts required Piston seal, Piston, Dust seal, Dust seal retainer

 

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Clean bore ready for piston

 

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Fit piston seal

 

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Slide piston into bore

 

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Fit dust seal

 

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Press seal into groove use something blunt as not to damage the seal (One of the utensils off her George Foreman wash it and put it away before she notices)

 

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Slide retaining ring into outer ring of dust seal

 

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Job done

 

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Hold on a moment.....

 

On my J-spec fronts the calipers sit in a separate aluminium cast housing that bolts onto the slider. Those look like they are one-piece iron jobs, like my rears. Are there two different designs?

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They are front calipers off a 97 NA, and as you say cast iron.. I dont know much about the different specs between models but these once removed from the caliper hanger have four male torx bolts so they can then be split in two

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  • 3 years later...
  • 1 year later...

The "edit" button is to the left of the "reply" button. I know you aren't new but it does elude some.

 

You will most likely have had Jspec calipers as standard, the question is whether or not any previous owners have upgraded them. It is very easy to tell simply by looking at the calipers front and rear. There are many many pictures on this very forum :)

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sorry i should have put a few quotes in my question but reading the thread back i now understand mine are the cast ones .

I already now that they are the 2 pot j-specs .

Just having trouble with my caliper seizing slightly after recently changing my pads and discs .

 

just wondering the best/esiest way to remove my pistons and replace the seals with a new piston and seal kit , As i will be doing this on the road side so need a few tips if possible .

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sorry i should have put a few quotes in my question but reading the thread back i now understand mine are the cast ones .

I already now that they are the 2 pot j-specs .

Just having trouble with my caliper seizing slightly after recently changing my pads and discs .

 

just wondering the best/esiest way to remove my pistons and replace the seals with a new piston and seal kit , As i will be doing this on the road side so need a few tips if possible .

 

 

If you have braided lines then you will either need 4 cap ends to fit the linse or you will need to replace a fair whack of brake fluid once you are done. If you have teflon lines all you need is 4 clamps to clamp the lines.

 

Clamp the lines and remove them from the caliper using, I think, a 10mm spanner (preferably a decent pipe spanner)

Loosen the 2 large bolts that hold the caliper on. These things are really on there so you need a LOT of leverage, rotate the steering as required to gain access.

Pull off the caliper, this may be difficult if the disc has a lip, you could try prising the pads apart to help, brake fluid will spurt out the hole though so be ready.

 

Take inside:

 

Remove pads

Remove ring clips using long nose pliars

remove boot seals

Remove pistons (This can be a bit tricky, if you can get the reverse L-Shaped pliar things this will help massively as you can pull them from the inside)

Remove piston seals (Piece of pie, just use long nose pliars, don't worry about damaging them you will be replacing them anyway)

 

You are now at the start of the above guide :)

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  • 2 years later...

I've struggling with getting the dust cover located in the cylinder (the bit where bromy uses the George Foreman tool). There doesn't look to be enough clearance between the piston and the cylinder wall to fit anything down there. The gap seems to be narrower than the circlip itself. I've tried pushing the piston all the way into the cylinder in the hope that the narrower bit of the piston gives me the room I need to push things down there, but no joy with that.

 

I've also tried a novel method where you fit the dust cover to the base of the piston, stretch it out to fit it into the cylinder groove, fit the circlip, then push the piston in: no luck there either but I might try that again with circlip pliers.

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I've tried pushing the piston all the way into the cylinder in the hope that the narrower bit of the piston gives me the room I need to push things down there, but no joy with that.

 

 

This the key, it's not a nice easy job because as you go around the wire wants to pop back out when you get to the last quarter, but with persistence you'll get there.

 

With the piston fully back place the seal on top and then grab one of the metal ring ends and go in vertically at first and push down and in to get that end located. Try and hold it down as you turn the ring more horizontal and push the rest down (it has to go down a bit further than you think) and after a few tries you should get the ring seated.

 

Focus on getting a nice solid quarter of the ring in the groove first then proceed by having the lose ring end on the tip of your first finger and it pulling it in towards the centre of the piston slightly ie reduce the rings radius and have you thumb pushing the next section down a screw driver can help if you are careful and don't have the foreman tools!

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