torque for clutch pressure plate

[stuchman1]

Hi everyone,

We're in the middle of our engine / transmission assembly. Gen 3 Coyote, standard Ford M-7560-T46 clutch kit, TKX transmission.

2 questions: first about torque specs - the Ford installation instructions for this clutch say to torque the pressure plate bolts to 12-24 ft-lb. FF instructions say to torque to 35 ft-lb.. Which is it? I'll be honest and say we already torqued to 35 so hopefully that's OK.

Second, the clutch instructions also say "the throw-out bearing supplied in the kit must be used. The use of aftermarket replacements may result in a loud squealing noise." Interestingly there is no throw-out bearing in this kit, so it's not clear what Ford is talking about. Instead, we're using the hydaulic throw-out we purchased with our kit from FF, which is the Mcleod 1406-30. Can I anticipate success or a loud squealing noise?

Thanks!
ST

[StangRacer]

I would suggest looking up the torque values for the diameter, the thread pitch, and material the bolts are made of... If you over torque a bolt beyond its yield, it's possible that it may loosen. The bolt, or screw, is actually held tight by the tension of the stretch put on the bolt when it is tightened with the wrench. I am not familiar with Coyotes and don't know the diameter or thread pitch of the pressure plate bolts but I can't imagine it would be too difficult to find.

[stuchman1]

Good idea. To get that info I went back to the Ford website to look up the bolts and their specs. They don't list the specs of the bolts but lo and behold there's a manual for these bolts, and that instructs me to torque to 46 ft-lb plus 60 degrees.

So between Ford's conflicting instructions and FF, it appears I should torque to somewhere between 12 ft-lb and 46 plus 60 degrees.

Sure I can look this up but with such a wide range in the instructions and being uncertain of the bolt metal composition to inform my own research, I'm hoping others on here can tell me what torque they've used and accompany that with the usual test of time comment that "40k miles later, the bolts are still intact".

I also already have the bellhousing on and I'm assuming those are single-use bolts that come in that $85 kit, so I'm really hoping that the experts on here tell me that 35 is the correct answer and I'm good to go.

Thanks!
ST

[StangRacer]

I tried to find the torque values and bolt sizes... I didn't think this information would be so difficult to get a clear answer. I did some digging and found the FRPP replacement bolts, part# M-6397-B46, which lists the bolts as 10MM x 1.5. The directions from Ford state, as you found, 46 lb-ft plus 60 degrees. It also states these bolts are torque to yield so they are a one-time use.

For a grade 10.9 10MM x 1.5 the dry torque value is 51 lb-ft and for a grade 12.9 the dry torque value is 57 lb-ft. The torque should be reduced 15%-20% for lubricated or plated bolts. Unfortunately, you can't convert degree of rotation to total torque due to there being too many variables.

I tried to find the ARP equivalent, but they don't list pressure plate bolts for the Coyote. At least not that I could find... The FRPP part# M-6397-B46 is listed for a 4.6 and 5.0 Coyote. One would think the ARP kit for the 4.6 would also work for the Coyote but the 4.6 ARP kit only comes with 6 bolts... maybe the bolt sizes are the same you would just have to purchase two of the ARP sets for the 4.6. If you don't want to use the Ford TTY bolts it may be worth a quick call to ARP in the morning.

If you want to use the Ford TTY bolts you can get a cheap angle gauge on Amazon for less than $20. They look cheesy but should work fine as all you are doing is measuring the degree of rotation.

[Jeff Kleiner]

Angle gauge is not necessary…60 degrees is one flat of a hex head bolt. After reaching your torque value mark the point of one flat, rotate the bolt until the next flat is at that point and that’s your 60 degrees.

Jeff

[stuchman1]

Wow. That's so helpful. Thanks so much!

[rich grsc]

Use the torque spec of the bolt manufacturer. The specs for a Ford bolt might be different than an ARP bolt.

[stuchman1]

So a maybe dumb follow-up question, but I never let that stop me! 😊



Based on the super helpful discussion above, the pressure plate bolts need to be tightened / torqued higher. We can reach them through the clutch fork cutout in the bellhousing, so I can probably tighten the pressure plate bolts without removing the bellhousing and its non-reusable bolts. (There’s no clutch fork because we’re using a hydraulic clutch with throw-out bearing. We’ll just have hydraulic lines going through that cutout.)



So my question – the pressure plate bolts came with threadlocker on them. We installed them several days ago. Of course threadlocker you apply yourself can’t be just retorqued after drying, but when the threadlocker is pre-applied, it’s already dry when you use the bolts, so I’d think increasing torque shouldn’t be an issue. (They’re currently torqued to 35 ft-lb and I need to get them to 46 plus 60 degrees.)



Am I wrong? Can we just re-torque the bolts?



Thanks!

[Mike.Bray]

we're using the hydaulic throw-out we purchased with our kit from FF, which is the Mcleod 1406-30. Can I anticipate success or a loud squealing noise?

I don't think you'll get a loud squealing noise but there's a fair chance that McLeod HTB will fail. They are the bargain basement of HTBs. Ram is better, Tilton is by far the best. Considering what you have to go through to change it I certainly wouldn't take a chance with it.