Looking for a better clutch fork
Anybody know if someone makes a aftermarket stronger than OEM clutch
fork? I have an ACT strip/street pressure plate and disk and I replaced the original clutch fork with a OEM clutch fork about 6,000 miles ago and that one is now broken. Or what about shot peening or heat treating the OEM clutch fork for added strenght? How do you really big horsepower guys with race clutches deal with the weak OEM clutch fork? Thanks jaj1 |
Any photo?
BC
Originally Posted by jaj1
Anybody know if someone makes a aftermarket stronger than OEM clutch
fork? I have an ACT strip/street pressure plate and disk and I replaced the original clutch fork with a OEM clutch fork about 6,000 miles ago and that one is now broken. Or what about shot peening or heat treating the OEM clutch fork for added strenght? How do you really big horsepower guys with race clutches deal with the weak OEM clutch fork? Thanks jaj1 |
Photo of what, the clutch fork? It's still in the trans. I can see through the inspection hole the clutch fork is cracked right by the roll pin.
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I bought a new one recently for a customer's clutch job - he had the ORIGINAL clutch, everything on the car (original owner!). Anyhow, his clutch fork was fine, but I noticed no difference between the original part and the new part - they looked identical. Dunno if Mazda did some sort of treatment or something.
Are you doing a lot of drag racing or something? I just can't see how one can break again THAT quickly. That said, I don't know of an easy replacement. I almost want to say I've seen Japanese tuners with an aftermarket part, but you'll have fun finding it and finding a good source to buy it from. You could also consider going with a multi-plate clutch. Tons of clamping power, but less stress on the engagement/release system. Dale |
Originally Posted by DaleClark
I bought a new one recently for a customer's clutch job - he had the ORIGINAL clutch, everything on the car (original owner!). Anyhow, his clutch fork was fine, but I noticed no difference between the original part and the new part - they looked identical. Dunno if Mazda did some sort of treatment or something.
Are you doing a lot of drag racing or something? I just can't see how one can break again THAT quickly. That said, I don't know of an easy replacement. I almost want to say I've seen Japanese tuners with an aftermarket part, but you'll have fun finding it and finding a good source to buy it from. You could also consider going with a multi-plate clutch. Tons of clamping power, but less stress on the engagement/release system. Dale I know, I find it a little weird too that I have broken another clutch fork so soon. I thought I read another thread that said Mazda reengineered the clutch fork in later years. Evidentially from what you are saying you did not see any difference in the old and new forks. Can someone else confirm if Mazda made changes in later clutch forks? |
So I take it no one has tried heat treating and or shot peening the OEM
clutch fork for added strenght? |
It's a cast part - there is only so much you can do with cast iron to make it more resistant to cracking and breakage. It seems to me that the second one you got was unlucky. Heat treating/cryo/etc will cost as much as a new one, I would guess, but if it last longer it may save on the future labor cost.
Dave |
Originally Posted by dgeesaman
It's a cast part - there is only so much you can do with cast iron to make it more resistant to cracking and breakage. It seems to me that the second one you got was unlucky. Heat treating/cryo/etc will cost as much as a new one, I would guess, but if it last longer it may save on the future labor cost.
Dave I had an interesting situation w/ mine tho, cuz there was a throwout bearing flying around in the cluch apparatus, and it eventually got in the clutch fork, and thus pressing the clutch put enough pressure to bend the throwout bearing, and break the clutch fork from one side! :eek: Man, that was a sight to see... Will cryotreating a cast iron part help much in strength? Also, IIRC, Mazda did indeed upgrade the part in recent years...supposedly stronger. The forks almost always break when you're using a heavy duty aftermarket clutch. I don't think I've heard of them breaking on a stock clutch. I'd be all ears if someone else makes an upgraded fork. Dale, that's a real good idea...a twin disc = less stress. Hadn't thought of that. |
Everyone says the part is upgraded, but I didn't see anything substantial. No extra bracing or anything obvious. Could be a better grade of iron, heat treated, who knows.
Really, I'd just toss in another new one and chalk the last one up to bad luck. Dale |
Thanks guys for your input. Looks like no choice but OEM.
I just hope this one last longer than a few thousand miles. (geez) jaj1 |
I had the same problem with clutch fork busted with the Extreme pressure plate and ACT clutch.
I had a buddy at Lockheed toss in their heat-treat oven and so far ZERO problems after 25k miles and still going strong. |
Originally Posted by FDNewbie
Will cryotreating a cast iron part help much in strength?
If it's not a martensitic steel, the cryo won't do anything. It's possible that Mazda switched the casting heat treatment or material without any visible difference. It would take a composition or hardness test to begin to determine if there is any difference. Dave |
Hmm?
hmm?
I have 9.5 aluminum flywheel ACT street strip pressure plate and Clutch I find it hard to get into 1st at a stop after it gets hot after spirited driving and on track days it's a Bit$h , it gets locked out from 3rd to 4th I have to wait for the rpms to come down and pump the crap out of the clutch pedel ! I did find the mounting bolts for the pressure plate to the flywhele to be loose I retighted them through the service plate an used locktight red. it seem to help but it still comes back. I was thinking SS braide clutch line , or pressure plate springs were too soft when hot ! |
Originally Posted by Hot Canine
I had a buddy at Lockheed toss in their heat-treat oven and so far ZERO problems after 25k miles and still going strong. My guess is the replacement forks are already heat treated because the casting itself looks exactly the same, yet a new part number was issued. |
Originally Posted by HotWheel
hmm?
I have 9.5 aluminum flywheel ACT street strip pressure plate and Clutch I find it hard to get into 1st at a stop after it gets hot after spirited driving and on track days it's a Bit$h , it gets locked out from 3rd to 4th I have to wait for the rpms to come down and pump the crap out of the clutch pedel ! I did find the mounting bolts for the pressure plate to the flywhele to be loose I retighted them through the service plate an used locktight red. it seem to help but it still comes back. I was thinking SS braide clutch line , or pressure plate springs were too soft when hot ! Dale |
Originally Posted by DamonB
My guess is the replacement forks are already heat treated because the casting itself looks exactly the same, yet a new part number was issued.
I assumed Mazda made it out of a stronger material (or heat treating, which I wasn't aware of), hence the new part number. |
Originally Posted by DamonB
25k is nothing. Until it lasts 250k we can't be certain heat treating was a help.
My guess is the replacement forks are already heat treated because the casting itself looks exactly the same, yet a new part number was issued. When the original fork busted it wasn't near the heat treated area. |
On mine the arm on the on the clutch fork cracked where the roll
pin goes into the the fork shaft. It is a very small crack but if you have someone else push the clutch pedal while you look through the inspection hole you can see the crack spread open a bit. Again the symptoms are more free pedal travel at the top of the pedal, the clutch grabs very close to the floor and there is clutch chatter when first engaging the clutch. |
I welded around the pin holes to build up the thickness of the part with nicad rod . I removed the plastic bushings and made new ones out of oillite brass .That was about 6 years ago and still good .
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Originally Posted by DaleClark
That sounds like more of a hydraulic problem than a clutch problem to me. Yeah, I would definitely start with a braided stainless line and a good bleed/flush of the clutch hydraulics. If that doesn't totally help, look into a new master and slave cylinder, especially if you've got high mileage on the parts.
Dale the next fix. I have 53k on the body , I would hope it was not the master cylinder ! I'll let you guy's know. |
Def. bleed the system first...the whole pumping thing sounds like there may just be an air bubble in the lines...hopefully that's all it is...
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