Roasted u-joint

[rocket366]

If you over tighten the U bolts there will be bearing failure.

The grease fitting/passage is a weak spot...

Especially manual trans cars where the driver can shock the

driveline by popping the clutch....who me?.

Stay away from a greasable U-Joint for high power cars OR

clock the joint so the rotation squesses the grease fitting

instead of trying to pull the joint apart at the fitting!

Make sure the cups are seated in the rear axle yoke

BETWEEN THE TABS and tighten the U-Bolts with a 8 in

wrench and JOB DONE!

I've never lost a driveline at the track from a failed U-joint

but there was that time I spewed 90W oil all over from

breaking a 9 in pinion shaft in two...agressive launch I guess

Paul

 

[Mister 4x4]

Wow, that's scary. What transmission and type of driveshaft are you running? Mine is a custom made aluminum shaft with 1310 joints at the rear diff, U-bolt style. I had to get a custom made shaft after I installed the 4R70W transmission.

Might want to install a shaft loop underneath your car... I have an X-pipe exhaust system that prevents the shaft from dropping right out of the car, serving as a sort of shaft loop!

I have an AOD transmission, with the stock '71 FMX driveshaft using an OE-style replacement U-joint into the stock 9-inch (I don't recall the part number). I also pieced together my own AOD conversion kit with parts from this site: http://www.transmissioncenter.org/classic_mustang_to_aod_conversion.htm

Even though nothing bottoms out or anything, I think I still need to whack about an inch off the stock driveshaft for more peace of mind regarding the slip yoke travel - there's only about an inch of inward travel left on the slip yoke - 2 would be better.

I also have an X-pipe exhaust, but that won't help if the rear U-joint lets go. I might look into a safety loop, but my pal Jim said I most likely just snugged down the U-bolts when I put the 'shaft in the car and forgot to properly tighten them - easy enough to do considering how much was going on at the time between running the shop, helping customers, and all the little tasks I had to do in rebuilding the car. Really odd for him to cut me slack like that, too.

Just unnerving to have something like the driveshaft fall out under 30 mph on basically the maiden voyage when everything else is going so well... and not being able to do anything to fix it because of A. no ground clearance to get under the car, B. no tools, and C. no spare parts. Also sucks paying $60 for a flat bed tow when you're only 4 blocks from the house. :shootself:

 

[rocket366]

With the rear end supported by stands or being on the ground measure from the

center (U-Joint Cup) of the rear yoke to the center (U-Joint Cup) of the trans slip

yoke with the trans yoke pulled rearward 1 inch from max inward toward trans.

That measurement is your DL length

Paul

 

[Mesozoic]

You might want to consider upgrading to a 1350 joint. IMO you are making way to much power for a 1310.

I did actually consider this. However, this would require chopping up a reasonably freshly fabricated aluminum driveshaft to fit the larger joint... and then, the front joint would need to be redone and rewelded as well since it would surely be the weak spot if left alone. Finally, the U-bolt style fastening mechanism is really not the best way to go. Ideally, I'd find a pinion yoke that fit the Ford 9" axle with a flange mount (like a late model 5.0L Mustang) instead of U-bolt flange. My old '89 5.0L has a blown 302 that generates over 600 ft-lbs of torque and I've never experienced any u-joint issues with it (many more miles than the '71 as well).

In the end, I'm sure that the aggressively tuned 4R70W transmission, with its triple clutch converter keeping things locked at throttle levels where a stocker would be unlocking, is not helping. I'll have to be really careful about reinstalling the repaired shaft.

 

[Mister 4x4]

With the rear end supported by stands or being on the ground measure from the

center (U-Joint Cup) of the rear yoke to the center (U-Joint Cup) of the trans slip

yoke with the trans yoke pulled rearward 1 inch from max inward toward trans.

That measurement is your DL length

Paul

If I'm reading this right, I already have the right length drive shaft then... I only have about an inch of inward travel on the slip yoke before it "bottoms out" inside the transmission. The factory rubber dust cover is slightly crushed with the shaft installed and suspension at rest (on its wheels) - which is why I was thinking another inch would be what I need.

I'll be having it up in the air on a lift again soon, though - so I'll take a better measurement to be sure. Thanks for the advice! ::thumb::

 

[Mesozoic]

Is it a difficult job to replace the pinion yoke? I know that my axle was built up using a solid collar install of a crush sleeve. Not sure whether I should attempt to do this myself or not...

 

[rocket366]

The yoke replacement procedure is very controversial.

What is wrong with the yoke you have?

Paul

 

[Mesozoic]

The yoke replacement procedure is very controversial.

What is wrong with the yoke you have?

Paul

Mine is chewed up from the failure of the u-joint. The driveline guys said it would be wise to replace the yoke. I have a Moser unit in hand, complete with new u-bolts and hardware, but not really sure I should attempt replacement myself.

 

[TommyK]

Is it a difficult job to replace the pinion yoke? I know that my axle was built up using a solid collar install of a crush sleeve. Not sure whether I should attempt to do this myself or not...

With a solid sleeve it should be no problem. Change yoke and torque pinion nut to 125 ft/lbs. This is one of the advantages of running a solid sleeve.

 

[Mesozoic]

Is it a difficult job to replace the pinion yoke? I know that my axle was built up using a solid collar install of a crush sleeve. Not sure whether I should attempt to do this myself or not...

With a solid sleeve it should be no problem. Change yoke and torque pinion nut to 125 ft/lbs. This is one of the advantages of running a solid sleeve.

Ok, thanks very much. I believe I just need to find an impact socket that large enough to fit the pinion nut at this point.

 

[mjlan]

Loosening that nut is fun. Got something to hold the yoke?

 

[tony-muscle]

I am following this thread with a lot of interest. I am wondering if i should add a shaft loop to my setup for safety. Since i am in the process of redoing the floors and installing the suframe connectors should be easy. I have tinman connectors so i was looking at the shaft loop they sell which welds to the subframe connectors. My question then is, once this is welded in place the loop is fixed, so am i assuming right that when installing the axle does it go in and out the loop with ease?


Also, where does the loop sits with respect to the shaft? Does it end up in the middle? Can someone share a picture?

1971 M-code Mach 1

 

[Mister 4x4]

I would think that having a safety loop securely fastened in several places with bolts would suffice. It's really only there to make sure the shaft doesn't go bonkers and tear up the floor while you're slowing down... which, I'm pretty sure you'd be slowing down if it had to start doing its job.

The ones I'm thinking of are more like tubes... kind of like the ones on monster trucks. To be most effective, you'd need at least two of them close to the end of the shafts near the U-joints. Depending on the size of the loops, it might be tough to get the shaft mounted once they're in-place, hence the idea of going with at least one of them bolted in, rather than permanently welded in-place.

Just my thoughts.

 

[jbojo]

Someone correct me if I am wrong but don't these go about a foot or so past the front U-joint? I thought that these are used in case the front joint fails and drops down and acts like a pole vault. If the back fails it would just drag along. If that's the case there would be room to remove the driveshaft with it installed.

EDIT: Just saw Eric's response and I have seen some with 2 of them installed. I didn't think about the bouncing up and down part.

 

[tony-muscle]

Thats why i thought you could have one towards the middle or 1/3 from the front. In that way it should keep the driveshaft from going crazy in case the u breaks.

Hence, my question that if it is welded in place will it hinder installation or be in the way of the exhaust. It will be nice to see pictures of different setups.

The secondary advantage of the shaft loop could be added frame stifness.


The installation instructions of the tinman shaft loop say to place within 6" of front u.

http://www.tinmanfabrication.com/index.cfm/page/ptype=product/product_id=127/category_id=76/mode=prod/prd127.htm

1971 M-code Mach 1

 

[Carolina_Mountain_Mustangs]

I have not seen one in the rear only in the front and they are usually elongated a little. It should not interfere with getting the driveshaft in and out. I have broken many in the rear and the shaft just comes rolling out the side because it pulls out of the transmission. I have broken in the staging lights at strip and never started the timer the car never moved and the rear u-joint snapped. That was with a 100 hp flathead V-8 back in the 60's. I broke more transmissions, u-joints, blown clutch disc, broke axles, sheared centering bolts in springs, busted bearings in rear with that flathead than all other cars combined. Had lots of torque but no rpm.

My F-150 super crew I bought new in 2002 has only had the drive shaft out once to lube joints in 260,000 miles, no grease fittings. I pulled at about 125,000 and packed with a good molly wheel bearing grease. I have towed camper, too many mustangs and broke a 3/8" log chain trying to get an old truck out of the field and never changed a joint. Did have pinion bearings go out at about 180,000. I really like the aluminum driveshaft's with the flange mounts for the rear, solid and strong.

David

 

[TommyK]

Is it a difficult job to replace the pinion yoke? I know that my axle was built up using a solid collar install of a crush sleeve. Not sure whether I should attempt to do this myself or not...

With a solid sleeve it should be no problem. Change yoke and torque pinion nut to 125 ft/lbs. This is one of the advantages of running a solid sleeve.

Ok, thanks very much. I believe I just need to find an impact socket that large enough to fit the pinion nut at this point.

Careful with the impact gun. It beats on the pinion bearings and can flat spot the rollers.

 

[Jeff73Mach1]

Front driveshaft loop should be no more than 6 inches behind the front u joint. If you use the weld in one I really does not interfere with removal of the driveshaft. If you bolt them to the floors , the proper location should catch both the floor pan and front seam of the seat pan for proper strength.

Rear loop is overkill for most people's usage.

 

[tony-muscle]

Front driveshaft loop should be no more than 6 inches behind the front u joint. If you use the weld in one I really does not interfere with removal of the driveshaft. If you bolt them to the floors , the proper location should catch both the floor pan and front seam of the seat pan for proper strength.

Rear loop is overkill for most people's usage.

Does it interfere with the exhaust?

1971 M-code Mach 1

 

[Mesozoic]

I was only planning on using the impact to remove the nut, but I've since then decided to have my friend, who owns a transmission shop, to sort it out for me instead. That way they can check the angles accurately while the car is on the lift and also take a look at a few other things.

My X-pipe is so large and in the way of the front u-joint that it serves as a loop all by itself. The rear, as mentioned earlier, would eventually pull out of the tailhousing and roll away. If I were racing a bunch I would definitely add a loop, however.

I'm also a huge fan of the flange mount style of connection to the rear axle. I believe this is called a "companion flange" mount. There are some options out there, including an OEM factory style yoke conversion using some kind of Lincoln: http://www.currieenterprises.com/cestore/productsRE.aspx?id=3995

Alternatively, there are other companion flanges yokes for the Ford 9:

• http://www.quickperformance.com/Ford-9-Companion-Flange-Round-Billet-Yoke_p_20368.html
  
• And if you must, you can run a Toyota companion flange: https://www.trail-gear.com/TG/DRIVELINE_FLANGE__FD_9_TO_TOYOTA/i_0_0_4519/_300843-KIT.aspx#.VnZC6FJumPU