Safety of rear forks to chassis

Hi all-when I disassembled my suspension, one of the rear forks was seized to the frame. I had to shave a portion of the welded bolt off to get it taken apart. I am now re-assembling, and the nyloc nut is very close to the end of the bolt, once the two "C" washers are in place. I'm currently torqued to about 55 ft/lbs(maybe I could go to 60 and buy another thread?) I'd love for you to take a look at the photo, and tell me if you think there may be a safety issue with the limited clearance the nut has on the bolt. I'd like to address it now. (or maybe, removing one of the "C" washers on each of the forks would be sufficient?) thanks.
Image Unavailable, Please Login

 

What exactly do you mean by this?

Once everything is clamped additional pressure stretches the bolt. I don't recommend stretching the bolt more than factory torque values, especially not enough to get noticeably additional threads showing. You'll have a fracture at the thread root for sure.

I wouldn't be super worried about the amount of threads showing. It is fully through the nylock. I would consider using a new nylock as a matter of course. Those C washers are shims for alignment. You can't just add and remove them on a whim without alignment consequences.

 

FWIW-aircraft require at least 2 threads showing to meet specifications. That seems like a good practice.

 

Ahhh. hmmm. I have new nyloc nuts i can use, but i dont think i'm gonna get 2 more threads showing....votes?

 

Colin Chapman would be embarrassed and angered by 2 useless threads making the bolt heavier than needed!

If the nut and bolt have all threads engaged, then extra threads protruding beyond the nut are doing absolutely nothing (from a mechanical strength perspective). The picture you posted is absolutely perfect.

 

I would definitely replace the fork. Even if the nut turns a half turn it won’t be engaging the nylock properly. Others may be right that it is fine but I definitely would not take the chance.

 

Just use some blue Loctite on the Nylock nut threads?

 

Wouldn't take the chance... I'd always be worrying that the thing would come loose.

 

ahhhh, votes down the middle.....the plot thickens!

 

it would seem colin chapman suffered many mechanical failures on his G.P. ventures in the quest for lightness.
ettore bugatti and other contemoraries esqued brakes to keep the pilotti moving.

on the other hand, many owners stressed brakes, to go deeper into corners and possibly pass their opponent.

personally, i'm of the school of brake stoppers. especially if your contract is up and you decide to say f**k it!

the gearbox is not a good decelerator as most expect.

 

Don't see a problem if it's fully tq'd and the bolt sits flush. Do see an issue if you need more for alignment reasons.

That's not a crazy expensive part, the usual breakers should have one for a $100 or so. I'd say you could weld in a new bolt, but the hassle of cutting out the old one, modifying a bolt to fit etc.. would exceed just getting a good used one.

End suggestion... Buy a replacement one.

 

I think the "two threads showing" is just for the purpose of having a standard that is easily inspected rather than any physical safety aspect. In regards to nyloc nuts however they are generally considered one time use and should be replaced with new if removed.

 

I would use it as is and sleep like a baby. As a matter of course I always use blue Loctite on all fasteners that are not to be disassembled on a regular basis. A few drops would do a better job than the nylock anyways especially one that has been previously used.

 

99 times out of 100, totally on board with that. Likely hood of the nut getting loose is very low, blue loctite would seal the deal on it.

This case is odd, why did the bolt have to be cut to remove? And if the lower control arm needs to be shimmed further for alignment.... Well that's not possible.

 

Thanks all. So, to back up and explain how I had to cut an inch off the bolt in the first place...

When I was stripping the suspension apart, the nut/bolt that fastens the fork to the lower lever was oriented with the head towards the rear bumper, so it was impossible to remove it with the fork bolt seized, due to lack of frame clearance. So, I did the usual-bathed it in 3-in-1, then brake cleaner, and attempted to drive it out with a hammer. It was still so seized that I mushroomed the end of the bolt(yes, in hindsight I should have seated the nut before driving, but what was only to be a little bit of force escalated in the moment, and things escalated with me and the bolt, and hey, it wasnt my proudest moment in hindsight ok?!?!). I had gotten it loose, though, so at that point, I thought my only way of removing the fork was to sawzall off the mushroomed portion of the bolt, which I did. From there, the job was easy breezy.

I'll go ahead and seat new nyloc nuts all the way around, while I'm at it. I've been loctite-ing all my suspension nuts as I go, for the record. My only other minor suspension issue is that the "rear" nut securing the front right lower lever is positioned relative to the frame in a manner in which the only thing you can get on it is a fixed end 22mm wrench-a socketed wrench wont fit, so I cant measure the torque; I'll have to do it by feel. Otherwise, feeling good about my newly rebuilt hubs, levers, steering rack, sway bars and brakes!

 

BTDTGTTS -- welcome to the club!

 

Do we all learn not to use a hammer on the end of a bolt by using a hammer on the end of a bolt? Yeah, probably.

 

I mean, I knew better. The question is really "did I know better in that very moment", the answer to which is a definitive no!

 

Hello,
IMHO I would look for some "elastic" nuts.
These are "shaped" at the top and will certainly "lock" on the bolt. They are also, for me, a ONE time use. They will also be a bit less tall than the nylock nuts and will show you some extra thread. I raced cars for 40 years and often replaced nylock nuts where I felt it was needed but I cannot remember one ever coming off. Yup I have a bucket of used nuts and I do reuse them in certain spots. This said I think you are good with your current fasteners but I would use RED loctite.
Please be as safe as you can ! I think safety is knowing what to do before hand.
John

 

As others have said, you have plenty of threads engaged and Loctite will be fine. I would use the old nylocs, get the alignment checked and then put new nylocs once aligned. If you lose more threads after alignment and have less than 6 threads, then change the fork. The 8kg-m is well below the max torque for an M14 fine thread and you get minimal benefit from more than 6 threads.