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Discussion Starter · #1 ·
So the front differential mount is completely rusted out (if you want to know how it happened, read the story below).

I see Dr. Rebuild has one for sale. I can weld, so that is not a problem, but does anyone have any other suggestions on where to get the mount? And any suggestions/thoughts on making sure I weld it in correclty?

Here's how I found this lovely bit of information out...

I was happily driving to play golf yesterday morning and on my way, pull up to a light next a very nice porsche vert. We smiled and hammered it on green. Wheels spun, shifted to second and popped the clutch with my foot in it and (((BANG))) a lound thud. Felt like I lost the whole back end of the car. I let off the gas and coasted. No noise. I put it into second and slowly let out the clutch and everything was fine, no noise. I accelerated harder and heard a click click click, but it goes away rather quckly as I get back to cruising. I down shifted and I heard the same click click click, but it also goes away rather quickly as the car settles in. Driving normally, there were no noises. So, I continue on and make it home with out incident.

Got under the car today and inspected the spring, trailing arms, half shafts and couldn't find anything, until I noticed that when I pullled on the half shafts the whole pumpkin and the bolt for the front differential mount were moving. So I stuck my fingers up under the mount and there is nothing left, completely rusted out. One big hole, which is now holding nothing...

If you have any thoughts on my above questions please let me know.

Thanks,
Chris
 

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Did the mount itself break ? That is pretty heavy gauge stamped steel and often covered in differential fluid crud which helps prevent corrosion.... :laughing:

I assume the front mounting point ripped off the frame ??

Is the pumpkin still bolted to the crossmember and is that crossmember rust free ? Even with the front mount loose it should not be freely moveable. Take your time and inspect closely what's going on back there.

You can find a new or used pumkin mount on the net, this is for example from MidAmericas website:


.
 

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It is a BIT unclear as to wether i'ts the horn tied to the diffy with the two cross bolts, OR part of the frame itself....I fear it's the latter, as I have spotted quite a bit of rust there over the years on many a shark/C2....

that frame has pockets there that collect water/debris from up north especially snow ice.....then rusts out quickly....the good news is if you can find the piece, as I RECALL it can be fixed with the body on the car.....

the bad news is....it's a PAIN IN THE ASS.....welding upside down and backwards under the car.....

:cheers:

OH, edit...on my car, I enlarged what drain holes there were by shoving a 1/2 inch bit through them....been a while though....
 

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Discussion Starter · #4 ·
Unfortunately it is the later...

It is the "cup" on the mount attached to the frame crossmember, not the mount that is attached to the differential with the two bolts.

The mount did not rip off the frame, but the bottom of the cup that holds the bushings and washers rusted out completely, so the banging on heavy acceleration is the differential lifting up and slamming down. When it slams down the u-joints click off what is left of the cup.

mrvette...thanks for the info. It is going to be a pain in the ass, I know that but I am glad to hear that you think it can be done with the body on.

Chris
 

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Your episode could have been a lot worse. When you get things ironed out, I'd consider adding a solid locating kit to the diff x-member mounts for security. :cheers:
 

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These pieces go under the diff cushions and between the front mount and frame... After taking the rear suspension apart and seeing the factory's mounting design for the first time, I felt a lot better a soon as I got the kit installed. Not everyone installs the front piece.

http://www.guldstrand.com/scripts/prodView.asp?idproduct=122
 

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These pieces go under the diff cushions and between the front mount and frame... After taking the rear suspension apart and seeing the factory's mounting design for the first time, I felt a lot better a soon as I got the kit installed. Not everyone installs the front piece.

http://www.guldstrand.com/scripts/prodView.asp?idproduct=122

This is a nice idea and most likely will help stiffen things up a little but $70 for two oversized fender washers and grade 8 bolts that can be bought at the hardware store ?????

.... wow...... :surprised :thud:
 

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This is a nice idea and most likely will help stiffen things up a little but $70 for two oversized fender washers and grade 8 bolts that can be bought at the hardware store ?????

.... wow...... :surprised :thud:
They're a bit more substantial than washers, but I admit Guldstrand's pricing has gotten up there. I paid a little over $30 when I got mine.
 

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They're a bit more substantial than washers, but I admit Guldstrand's pricing has gotten up there. I paid a little over $30 when I got mine.
Depending on your location (Orlando is too expensive) you can have these made at a local shop for less than that ...
VBP sells the discs for $40.
 

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AS I recall, I put urethane in mine, from VBP.....12 years ago...not a problem, yet.....been a few years since I have really completely examined the undersides of this car....I need find a lift and spend a hour going over crap like this just to ward off problems....
 

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Check to see if Caledonia makes a replacement bracket you can weld in place.
They make up a lot of the frame parts so I'm sure they'll have that.
 

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Caledonia? Thanks, I will check that out. Dr. Rebuild sells it for around $70.

Chris
Buf, I would take a hammer and cold steel chisel under there and tap around a goodly bit to see just perzactly what shape the rest of that frame is in....

go slo, and careful...no sense wasting time if that car was from the NE region there is a fair chance there is other crap going on and you maybe in for a seige....not the hugest issue in the joint, but frame parts/whole sections or a whole damn frame is/are available if you need it...but a good solid inspection by a experienced shark person is needed.....

if nothing else, your own safety....kinda tough finding your rear wheels preceeding you down the road....eh? :devil: :smack :cheers: :cheers:
 

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Buf, I would take a hammer and cold steel chisel under there and tap around a goodly bit to see just perzactly what shape the rest of that frame is in....

go slo, and careful...no sense wasting time if that car was from the NE region there is a fair chance there is other crap going on and you maybe in for a seige....not the hugest issue in the joint, but frame parts/whole sections or a whole damn frame is/are available if you need it...but a good solid inspection by a experienced shark person is needed.....

if nothing else, your own safety....kinda tough finding your rear wheels preceeding you down the road....eh? :devil: :smack :cheers: :cheers:

I agree with Gene ... I would make sure the rear crossmember is worthy
of welding to before buying parts. You may find yourself looking for a small
section of rear crossmember to replace a rotted section.

Good Luck ... hope it is only the bracket rotted out.
:buhbye:
 

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Discussion Starter · #16 ·
Thanks for the additional warnings guys. I have shored up this frame in numerous spots already (rear kickups, gussets, frame rails). There is no doubt that this is a NE car, that most likely saw some winters in its early days. I am somewhat bubba, but also most concerned about safety and prone to being over cautious. There are definitely a few extra pounds of steel making sure the frame is solid.

I have checked the crossmember recently and it is solid, I will be sure to check it again.

As a side note, it is the most disheartening thing in the world when checking the frame with a screw driver and watching it go through...

Chris
 
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