garcia85

Hello, first time poster, I had a quick question, I have a 91 4runner 4x4 and I dropped the differential along with the oil pan due to it leaking, well it's all back up and the CV Joints are in, the thing is that I hammered out the bolts pretty good so now the threads are somewhat screwed up.

Does anyone know the part or where I can purchase these bolts? they're used to connect the front differential to the CV Joints, 6 on each side, just went to a hardware store and bought some but they were not the right size. Might have to call the Toyota dealership to see if they can help out.

thanks in advance.

scope103

Oooh.

As you must have figured out at some point, those are NOT removable parts. You've simply buggered up your differential.

You can play around with different sized "hardware store" bolts, but none will ever fit right, because the piece you hammered out has a machined shaft (to fit the CV) and formed "barbs" to be pressed into the differential flange. The best you can hope for is to get some bolts that are "close," and tighten them up as tightly as you can. You're still going to have a problem with the cv slipping back and forth against the flange until you break it.

Tough luck.

garcia85

Oh sorry I don't think I was clear enough. Here's a diagram.

https://i.imgur.com/owqtjV9.png

I called the Toyota dealership and had to order a total of 12 bolts. They were like 3 bucks a peace. Yikes. Hopefully they're the right ones.

scope103

Your screen-shot was cut off; I assume you were looking at:

If the part you ordered was 90179-12047, those are usually called "nuts," not bolts. They mate to the studs shown in the following drawing on 41309F (shaft sub-assembly), which are NOT replaceable.


Whatever the name, I'm glad you got it figured out.

garcia85

Hey thanks for posting photo. You're right it's the actual bolts that I need, not the nuts. How are these not replaceable? I was able to hammer them out I was hoping I could hammer the new ones back in and then tighten them down.

Will this be a big issue when putting everything back together?

RJR

Couple of things: First, if you're ever going to hammer a bolt out like that, put a nut on end of it first so that the threads are protected. That'll save you buying new bolts.

Second, I honestly don't know why Toyota decided to make those bolts press-fit (by comparison, the bolts on the drive shaft flanges, which perform exactly the same function, are not press fit). What I do know is that it is not to keep the CV shaft from slipping back and forth on the flange. That's not how properly designed joints like that work.

The bolts are there for one purpose - to clamp the joint together with adequate force such that the friction between the flanges provides the driving force. There should be enough friction so that the flanges never slip with respect to each other. If they do, even a very small amount, and do it repeatedly, the nuts will eventually loosen and joint will fail.

The bolts should only experience axial stress, never shear stress. If they are experiencing shear stress, it means the bolt torque and resultant clamping force is inadequate for the application. Since in proper use the flange never slips, it really doesn't matter if the bolt has zero clearance or 1/4 inch of clearance in the hole, except for initial alignment purposes.

It is important to replace those bolts with the same or similar quality bolts. The torque value is quite high for the size of the bolt, beyond the rating of a grade 8 bolt, I think. I believe grade 11 bolts are required there.

wyoming9

iTrader: (1)

They are there for one reason to make it faster on the line when building

If you have been lucky enough to see a line in person it is pretty neat

I just put new bolts and nuts on my 92 runner with ADD and locking hubs I have had no problems

dark_fairytales

I am not an expert, but I do know this much; many of us have modded those bolts to no longer be press in, which make for replacing CV shafts easy and quick. We would grind off the splines and then install the bolt back ward so the nut is to the inside to the stub axle next to the differential. As for the quality and strength of the bolt, I would think Grade 8 is sufficient. There are many people running Grade 8 hardware for their driveshaft bolts without any issues. If the Grade 8 hardware can hold up too the torque of the drive shaft, without a doubt it can hold up to the lower torque force levels at the axle. Just get the bolt that fits the best with the strongest rating you can find, but do not go lower then Grade 8.

RJR

The torque on the CV axle shafts is actually quite a bit greater than that on the drive shaft, not less. For a locked differential the torque is mutiplied by the diff ratio ( e.g., 4.56), while for an open diff the multiplication factor is one half the diff ratio. (E.g., 2.28 for a 4.56 gear ratio).

While I'm sure grade 8 bolts are working for most people, they don't quite meet Toyota's specs. The bolts are 10mm. According the FSM standard bolt torque page, the standard torque for a grade 8 10mm bolt is 45 ft-lbs. The FSM states that the CV flange bolts should be torqued to 61 ft-lbs. That requires a grade 11 bolt to meet the Toyota standards. That's also the grade bolt that Marlin Crawler sells as a replacement.