Bent trunnion fulcrum

[karls59tr]

It appears as if the lower rear inner fulcrum bracket is cracked where it meets the frame....so the bracket is bent up making the fulcrum pin off center by about 3/8".That is it's pointing towards the engine about 3/8" instead of pointing straight back. Would this have a major affect on the suspension geometry or not make much difference???? I suppose I will have to relocate the fulcrum bracket and weld it back to the frame. In hindsight I should have done a frame off resto and it would have been easier to fix. Karl PS Can nyloc nuts be reused?

 

[karls59tr]

Correction: Should read "Lower Wishbone fulcrum pin bent".

 

[rlandrum]

I suspect that it will be impossible for you to reassemble the wishbone with the fulcrum pin bent off center like that. I would fix the issue and attempt to weld the cracked bracket to ensure it doesn't bend again.

 

[Twosheds]

PS Can nyloc nuts be reused?

The criterion for re-using fiber lock nuts in aviation is:

If you can't thread them on with your fingers, you may re-use them.

But, they are so cheap why not just replace them every time?

 

[martx-5]

Well, it's going to have to be straightened out. The fulcrum is welded in two places. At the inner bracket of the A-Arm, and again on the frame toward the front between the span of the A-Arm. The outer bracket is the one that is bolted on, but has a small piece welded to the frame where the bolts go through. Did that break also, or did it just come unbolted? Is there anyway you can post some pics so we can see exactly what your up against?

BTW, it's time for a little story. I had the same thing happen to me on a small mouth TR3 I owned back in the '70s. It was kind of a rat that I bought for $300. It was my daily driver for several years, and one day the left side front end (lower A-Arm just ripped off of the frame. I parked the car at the dealer I was swinging wrenches for, and bought a '67 Mustang from him for a couple of hunderd bucks. The car sat for about three months in the back of the lot. Someone came in and inquired about the TR3. I told him it was mine, and what the problem was. He said "Yeah, I can see that. What do you want for it??" I said "how about $300." OK was the reply. He gave me the money and showed up about an hour later with a buddy and a welding rig on his truck. He spent about an hour bending and welding and then drove the car away.

I wonder if that sucker is still going? :laugh:

 

[TR3driver]

The 3/8" by itself won't screw the handling up TOO bad IMO; but it's not going to end there. The break will continue to get worse every time you step on the brakes, until it rips loose entirely.

Had something similar happen to me on a TR3A I used to own; it quickly got so bad that the car would pull into oncoming traffic if the brakes were applied only moderately hard.

But I only paid $100 for it (not counting the ticket I got driving it home)

 

[TR3driver]

Oh yeah, Nylocs lose a significant portion of their holding power after just one reuse. More if the threads exposed above the nut are corroded or rough.

You can reuse them a few times; and then stretch the life a little more by smacking the top with a BFH to squeeze more nylon out into the center.

But my personal suggestion if you're going to own a TR3 is to just buy a box of each size (1/4NF, 5/16NF and 3/8NF) from a hardware supplier and use a new nut every time. Should cost under $20 (even Canadian) for a lifetime supply.

 

[karls59tr]

Does NF stand for National Fine? Would the selection of nuts you recommended replace most of the castellated nuts on the 3 suspension?

 

[karls59tr]

I'll try and post a pic of the bent fulcrum.

 

[martx-5]

Does NF stand for National Fine? Would the selection of nuts you recommended replace most of the castellated nuts on the 3 suspension?

Yes to both questions. However, there are some larger nuts on the suspension that these won't cover, but they will fit in many other places on the rest of the car.

I'll give you the pitch (threads/inch) also.
NF
1/4"-28 tpi
5/16"-24 tpi
3/8"-24 tpi

 

[PeterK]

Karl,

If an inner fulcrum bracket is bent so is the fulcrum pin that runs through them roughly 12" from front to back. To straighten the pin will require some heat. And you probably want to straighten the pin to spec in situ and then weld the bracket it runs through back to the frame. You can buy a new pin from Moss but it's a bear to do it right with the body on. I guess any method you choose, it's a real pain diy repair. Maybe you could find a guy like Randall sold his TR3 to come out and do it.

Don't forget the gas line if it's the driver's side that's bent.

PK

 

[TR3driver]

Would the selection of nuts you recommended replace most of the castellated nuts on the 3 suspension?

Personally, I'd rather keep a castellated nut where the factory went that way. Sometimes a Nyloc isn't appropriate, and cotter pins are cheaper than Nylocs anyway

I've also had even new Nylocs back off sometimes; especially on the driveshaft bolts and rear shock mounting bolts. For the driveshaft bolts, I eventually went with all-metal locknuts, which hold much better (but are more of a PITA to R&R). And my rear shock bolts are now high tensile SHCS (socket head cap screws) with Loctited nuts. My point being that a castellated nut and cotter pin is also more positive than a Nyloc.

 

[Tinkerman]

I couldn't agree more with Randall. With the castlated nuts and cotter pins you have a sure thing. I would also most certainly toss out the old crop of nylocks and replace them with new. Not enough money involved to take the chance.

Good Luck, Tinkerman

 

[AltaKnight]

I've also had even new Nylocs back off sometimes; especially on the driveshaft bolts and rear shock mounting bolts. For the driveshaft bolts, I eventually went with all-metal locknuts, which hold much better (but are more of a PITA to R&R).

I've had a vibration at about 40 mph recently; so last weekend I put the rear up on jackstands and checked the driveshaft ujoints. The joints are fine but all the nylocs at the front and back were finger loose hence the vibration.
The nylocs looked old so I replaced 'em which was a pain in the A*** to do around the exhaust system; of course with new nylocs you have to double wrench 'em all the way down the threads, not easy in cramped quarters.

 

[karls59tr]

Does Moss still sell the castellated nuts and if not are they still available from suppliers?

 

[roger_abbott]

Practically any fastener you could ever use is stocked by Fastenal (www.fastenal.com). According to their web site, they have three stores in your home town, Winnipeg.

 

[TR3driver]

TRF & Moss have several of them listed, so does MMC.
https://www.zeni.net/trf/TR6-250GC/261.php
https://www.mcmaster.com/nav/enter.asp?pagenum=3140

 

[DougF]

The practicality of reusing a nyloc nut is directly proportional to the safety value of the part that the fastening system is securing. Am I going to risk my safety and my car to a reused $.30 fastener?
The vertical link on my TR3 broke on the interstate at 65mph. I was very fortunate of the outcome. It could have been a very messy pick up for the local coroner. It wasn't fastener failure, but believe me, I will do everything possible to assure nothing like that happens again.

 

[DougF]

When buying fasteners, be aware that if the piece is oily, chances are it is foreign(keeps down the corrosion on the boat). I am very leery of imported fasteners. I have heard of many instances and am personally aware of several more where foreign products have failed causing incredible damage.
I'm not preaching doom and gloom, just letting the buyer beware. Past regulations have reduced the number of fastener failure cases, but I still believe it is something to be aware of at the time of purchase.

 

[vivdownunder]

Karl, as Randall so wisely said, it will continue to get worse until it rips loose. That can't be programmed to happen in the driveway.

Over many years I've seen cracks and breakages to the inner fulcrum pin mounts that made me shudder. And not just for the risk to the driver, but for any passenger, and other road users. Mostly the pins are pushed back like yours, and I put a lot of it down to prior accidents, or smacking a kerb hard. Todays grippy tyres add stress to the pin mount to frame welds. Whatever the cause, prompt repairs are needed for peace of mind.

Castellated nuts are re-usable (always with new split pins), but I support the notion that nylocs are a one way trip. Even if they weren't as cheap as chips, I'd never risk re-using one on a suspension.

Regards,

Viv.