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Is it a common problem with old jap spec front calipers?


FOSTA

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If your abit of a noob (like myself), but you like to explore and do things yourself.

I have abit of advice on bleeding the brake system witch I was unaware of. When you tighten the brake nipples ONLY NIP THEM UP! as today I've lernt the hard way and cracked my caliper! :(

 

But luckily for me Keron from extreme performance has One in stock at a good price :D

 

So this was a learning curve for me and hopfully this will keep outher noobs from making the same mistakes :)

Edited by FOSTA (see edit history)
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The commonest things I see in the trade are overtightened wheel nuts or bolts and overtightened bleed nipples. Neither need or should be anything like as tight as most people seem to imagine. Bleed nipples need only a light nip with one finger on a short spanner. Wheel nuts need a torque wrench until you are good enough to "feel" the right torque. You'll perhaps be surprised how little torque the makers dictate. Overtightening can deform hub faces, cause stud failures, and generally make puncture changes on a dark wet night a nightmare. Off topic I came around a blind bend on a fast country road the other day to find 4 people from one small car changing the wheel at the side of the road. 50 yards further up was a agteway, and 100 yards a quiet side turning. Quite why people risk their lives rather than driving on a flat tyre for a few hundred yards i don't know. I drive to the next exit on motorways if I am unlucky enough to get a flat, rather than risk the hard shoulder. I value me far above a tyre or a rim!

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ok this is going to make me sound like a right wolly!

 

i fitted the new front caliper and i proceded to bleed the system, now the pedel seemed abit spongy after we done the bleeding process!

so i checked for leaks etc with non to be found? so i tried bleeding the system again still with no joy! so i went over everything again but with a bright light and taking my time, only to find both my front calipers had hair line cracks in them at ther same place ! The bleed nipples!!!

 

Now i applied the same pressure to the rear nipples and they are fine. so its only the front calipers.

 

Now after i over tighted the first nipple i knew they just had to be ever so slightly nipped up! so i used a spanner and only slight finger pressure was useded to make a seal. And as soon as the fluid stopped i didnt tighten anymore!

 

So ive done a search and it seems that only the jap spec smaller calipers suffer from this! so thats the TT AND NA smaller calipers mine are 19 years old now so i imagine age has a big part of this problem.

 

I know im abit of a noob so it could be human error but im not totally usless and im quite confident i know what im doing after doing quite alot of research and taking to a few people in the know. so im sure its a problem with old jap specs

 

Im starting to think they might of freactured when loosening the bleed nipple as they where quite tight to undo! but im unsure at this point.

so i think i might just get myself a set of uk fronts or aset of d2's. :(

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Bleed, bleed and more bleed. When you think you've done enought bleeding, do one more. Or get a vacuum bleed kit, helps out a lot.

Also, is the bleed nipple at the top of the caliper? Simple thing I know but I spent months chasing a spongy pedal, turns out my UK spec rears were on the wrong sides, hence there was air in the top of the caliper.

Im not so proud I cant admit my mistakes.... :(

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Nothing whatsoever to do with the age of the casting, plain and simple over tightening. It's been well covered. Just because they are brake components, or wheel fixings DOES NOT mean they need a huge amount of torque! I am sure the J-Spec nipple torque is in the workshop manual

 

Yeah I understand Chris, but like I said I only used slight finger pressure.

I had a clear tube over the nipple and as soon as the air bubbles stopped coming out and a steady stream of fluid was visible , I slowly used my finger tip on the edge of the spanner and used slight pressure untill the fluid stopped coming out of the caliper. Any less pressure would of resulted in the caliper still allowing fluid to spill from the nipple.

 

Theses cracks are very hard to see, they are like a hair line and where only visible when a cleaned up the dirt around the nipple and used a bright light close up. Even then it was still quite hard to see, we only noticed as when I ran my finger around the area a small air bubble appeared.

 

I did learn my lesson the first time lol.

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Bleed, bleed and more bleed. When you think you've done enought bleeding, do one more. Or get a vacuum bleed kit, helps out a lot.

Also, is the bleed nipple at the top of the caliper? Simple thing I know but I spent months chasing a spongy pedal, turns out my UK spec rears were on the wrong sides, hence there was air in the top of the caliper.

Im not so proud I cant admit my mistakes.... :(

 

Hi swampy,

At this moment in time bleeding them will be pointless as both front calipers have cracked mate.

 

Cheers mate ;)

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This is just a few other threads I've found on it.

I spent hours reading up on this last night and I never found anything on uk brakes having this problem or aftermarket brakes.

Witch is why I now believe there is a problem with the smaller jap specs

 

http://www.mkivsupra.net/vbb/showthread.php?138695-Calliper-nightmare&highlight=Brake+bleed+nipple

 

 

http://www.mkivsupra.net/vbb/showthread.php?212146-Caliper-woes-I-don-t-believe-this!&highlight=Brake+nipple

 

 

A QUOTE from ROB D in that thread:

 

My j-spec caliper done the exact same! I've seen a few other reports of this!

 

I was doing a brake fluid change on mine, undone the nipple and it cracked the cast!

 

 

So even undoing the nipple can cause this to fracture as what I suspect happend with mine as they where quite tight to undo.

 

 

http://www.mkivsupra.net/vbb/showthread.php?250422-Brake-bleed-nipple-woes!&highlight=Brake+nipple

 

There is loads of threads on this now I've looked on google. It is only the jap specs that do this.

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