My New Diff Mount and Strap Project

[sweatybetty]

i would like to see if the bolt moves in that slot over time and stress

[Patcon]

8 hours ago, sweatybetty said:

i would like to see if the bolt moves in that slot over time and stress

I was wondering that too. Might want to make some witness marks to keep an eye on it.

[Captain Obvious]

Thanks guys! That pinch bolt is pretty tight, and I really doubt that it'll slip, but you're right that it could happen. I'll keep my eyes on it.

I can just reach the strap with a couple fingers with the car on the ground. That way I can check tightness without jacking anything up and crawling underneath. Makes it easy to tell without much difficulty if anything has loosened up. I'll keep you posted!

[sweatybetty]

a couple of hard pulls should tell the tale

[Captain Obvious]

Well any more evaluation will have to wait until the rains stop, which at current forecast may be.... Never?

[Zed Head]

Overkill, but you could put a jack under the nose of the diff and put some lift on it.  Disconnect the bottom mount so that you don't damage it.  Won't be surprised if you can lift the back of the car off the ground with it.  Assuming that the mating surfaces were oil/grease free.  I'm surprised sometimes that we don't consider the surfaces when bolting things together that require friction to do their job.  I'm sure that you did but it's often overlooked, with greasy parts assembled and bolts/nuts torqued.   You might even use some Loctite or similar to buy some shear strength if it slips a bit.

[sweatybetty]

external star washers should solve any slippage if there is any

http://www.almabolt.com/pages/catalog/washers/star.htm

[Captain Obvious]

Original pic links were dead (because photobucket sucks!!), so I refreshed the pics below.

I recently did some work on my front diff mount and strap and here are my findings from the project. It was my first time messing around with these parts.

Here is a pic of the old mount and original hardware. I'm replacing the mount because the rubber is soft and squishy. The original hardware holding the mount to the diff is hard to remove because the mount itself is partially in the way. It's much easier with the whole diff out of the car, but if you're trying to replace the mount without dropping the diff it's a pain in in the butt. I think you're supposed to remove the hardware using an open end wrench on the bottom and a box end up in the trans tunnel hump on the nut up top:

I decided that since my original mount was already 75% split and squishy, that I would just split it the rest of the way and pull the bottom part of the mount off which allowed me to use a standard socket on the bolt head. In other words, I finished the destruction of my old mount to get to make getting to the hardware easier. Here's my old split squishy mount:

When it came time to put my new mount in, I changed the mounting hardware scheme to socket head cap screws instead of the original hex head bolts. I don't know if this is old hat or not, but my custom hardware looks like this. Socket head cap screws on the left in this pic:

So what's the big deal about using SHCS there instead of hex head bolts? The SHCS allowed me to use a hex driver on my ratchet like this:

And tighten the bolts from the bottom like this. The hex driver clears the bottom plate on the mount so you don't have to deal with the original hardware anymore. If I ever have to mess with this thing in the future, it will be much easier to R&R. Box end wrench braced against the diff body to hold the nut on top and hex drive to tighten from the bottom, I found this much easier to work with than the original hardware scheme.

(Edit for new info) Only update I would make to the original procedure is that I would use a grinder to notch the diff mount plate a little bit to clear the heads of the socket head cap screws. The reason for that is the heads of the SHCS are taller than the original hex head hardware and even though I don't think I'm having a problem on my car, I can see the possibility that the lower plate of the diff mount may hit the heads of the screws if the mount is twisted enough. So just to be sure, I would take a little metal off the diff mount to clear the new screw heads.

But in any event, here's how easy it is to access the SHCS heads with the modified design:

I used 1/2-13 x 4 inch long socket headed cap screws. You could also use M12 SHCS if you can't deal with the English hardware on the Metric car, but since the English stuff is so much more prevalent and cheaper for me, I used Engilsh. I used the black oxide hardware below to test fit, but for my final install, I bought some new zinc plated hardware for corrosion protection. This pic was before I had the zinc plated parts bolts on hand:

[Freez74]

Good idea, I didn't think of that and used a grinder to make a notch in the mount for standard hex socket clearance.

[dutchzcarguy]

22 hours ago, Captain Obvious said:

You could also use M12 SHCS if you can't deal with the English hardware on the Metric car,

Hey Captain, i can't deal with english hardware on a Metric car!!! … I hate it!  ?  ….   btw... isn't that hex head called an allan key?   or is that tipically English to call it that? I've never heard of a SHCS bolt?  what does it stand for?   ( when Volvo made the p1800 there were also english bolts and things on it for a few years because they made them in England!  normally a Metric swedish car..)

 

EDIT... haha.. SHCS.... google... says   :  a socket head cap screw….  pfff..  we call it (Dutch) a: "inbusbout"   haha..  a bolt with an IN(side)  hex-hole... simple…  

Edited November 3, 2019 by dutchzcarguy

[Captain Obvious]

Yes, the Allen key is what goes into the head. I've heard them called all sorts of things here including Allen screw, but I believe the official name (here) is Socket Head Cap Screw (SHCS).

I'd rather call it an inbusbout.    I like it.

[german240]

@Captain Obvious Did you measure the belt lenght before install? I would like to prepare one, too (before I remove the old one). Great ideas!