Technical Rear shock absorber nuts

[tobywood13]

Hello, I’ve just started taking my rear shock absorbers out. I undid the first nut, which was pretty rusty, and now it is stuck in my socket and I can’t get it out no matter how much whacking I do. I’m thinking of buying a new socket and new nut, but I’m need them pretty sharpish as I have an MoT on Saturday!

I can’t find it on Ricambio or eBay, so was hoping to go to a local B&Q or similar and buy a matching nut. Does anyone know the specification required? It’s 19mm but I don’t know the pitch, or M number (whatever that is, I never know what that means).

Part number according to EPER is 15503811

 

[ZaphodB]

Put the nut back on the bolt for a few threads and use that purchase to wiggle the nut free from the socket head.

The M is the thread diameter! , the head size (19mm) is immaterial and never really referred to. (but is related to the thread diameter by the by)

The M in your case (based on a 19mm head and experience) is probably 12mm (so M12)

The pitch could be 1.75 or 1.25 for a M12 bolt (it's how many thread per inch there are)

I've just found several sellers selling "Fiat 15503811" - just google that term and you'll see them

(see attached chart)

 

[tobywood13]

Interesting info on the bolt size, I’ll try and get my head round that. Not sure the online sellers would reach me in time for my MoT.

I’ve tried putting the bolt back on and wiggling it, hammering it, pleading with it but so far no success. Tempted to just buy another 19mm socket and leave this one permanently fixed in place…

It was getting very hot as I undid it due to all the rust breaking, could it have friction welded itself to the socket?

 

[ZaphodB]

I’ve tried putting the bolt back on and wiggling it, hammering it, pleading with it but so far no success. Tempted to just buy another 19mm socket and leave this one permanently fixed in place…

It was getting very hot as I undid it due to all the rust breaking, could it have friction welded itself to the socket?

Naw, doubt that very much (you would have to have been going some to get to those temperatures), it's more than likely a combination of it's gone slightly off axis in the socket head and jammed itself, happens a lot.

Interesting info on the bolt size, I’ll try and get my head round that. Not sure the online sellers would reach me in time for my MoT.

That's metric bolts in a nutshell, there aren't any deviations from that chart for those sizes.

 

[tobywood13]

Naw, doubt that very much (you would have to have been going some to get to those temperatures), it's more than likely a combination of it's gone slightly off axis in the socket head and jammed itself, happens a lot.

I must introduce you to my supersonic ratchet set, very reasonable from Halfords…

So it’s just a physical blockage. In theory then some combination of hammering and other percussive persuasion should unstick it. I’ll try again tomorrow with some more violence.

 

[ZaphodB]

Don't hammer.... persuade

You need to put the socket in a t-bar or the rachet , and then use the t-bar or rachet as a lever at various points around the circumference of the nut (so probably the rachet is the more adaptable.

What I would normally do is tighten the nut up (i.e. turning in the opposite direction will eventually get to the tightness where it will release the jam)

 

[firstcar-Y10]

For reference, they are M12x1.25 thread nylock nuts (plastic insert on the curved side to stop it working loose), the 1.25 pitch is common to pretty much all the bigger fastenings round the car. It is the same thread as the wheel bolts, if it's stuck in a deep socket no good but if you've just got it in a standard socket, get one of the wheel bolts and start running the nut down the bolt, it should push itself out as the thread on the bolt pushes out the back of the nut.

 

[tobywood13]

What I would normally do is tighten the nut up (i.e. turning in the opposite direction will eventually get to the tightness where it will release the jam)

I'll give that a go, the other three nuts will have to wait until I've got the socket un-nutted.

It is the same thread as the wheel bolts, if it's stuck in a deep socket no good but if you've just got it in a standard socket, get one of the wheel bolts and start running the nut down the bolt, it should push itself out as the thread on the bolt pushes out the back of the nut.

Ooh, that sounds like a promising approach. I'll stick a wheel bolt in and see if that does it.

 

[tobywood13]

I haven’t had any luck with any of the suggested methods unfortunately. I contemplated leaving the socket and nut fused, attached to the wheel with the socket acting as the nut. This rubs against the inside of the wheel, however, so won’t do. Back to hammering

Even a 7 pound sledgehammer isn’t doing the job!

 

[Dragon Man]

i work in a scrap yard and deal with this on the daily.. with enough hammering on the side of the socket it will come off. a few hits one side then the other side. more hammer weight is not always the best thing to use. ideally you want quick short jabs from something like a 2 or 3 pound hammer. the aim is to rock it off.

now imagine trying to get the nut out without being able to wind it back on the thread.. thats what i have to deal with. guhh. i have it to an art now.

 

[ZaphodB]

I'm guessing the socket head is 12point, you're less likely to jam your nuts (oooo errr missus) with a 6 point type.

The 12 point type have more chance of jamming when you're really pushing some force through them, so to avoid the hassle if you're removing (or fitting) a bolt that requires some force putting into it use a 6 pointer

 

[tobywood13]

I'm guessing the socket head is 12point, you're less likely to jam your nuts (oooo errr missus) with a 6 point type.

The 12 point type have more chance of jamming when you're really pushing some force through them, so to avoid the hassle if you're removing (or fitting) a bolt that requires some force putting into it use a 6 pointer

Actually it’s a 6 point one that I managed to get stuck, somehow.

I’ve had far too many experiences with rounding nuts and bolts on my 1990 MX5 (made of steel with the consistency of wet cardboard) using my grandfather’s 60 year old 12 point set, so I’ve been using a 6 point set for the last year or so on the more troublesome fixings. This is the first time I’ve had any trouble with this socket set.

To be fair to it, the nut looks in great shape, it’s just a little wonky in the hex.

 

[ZaphodB]

Oooo wow

Maybe you've just lost too much of the nut width to corrosion.

Or the nut was made of cheese

 

[tobywood13]

Oooo wow

Maybe you've just lost too much of the nut width to corrosion.

I think that’s the most likely cause yeah. Good old 18.5mm nuts…

Annoyingly, the other three 19mm nuts for the rest of the shock setup all came off and went back on easily, using the antique socket set! Perhaps I was too quick to judge tools manufactured in, let’s see… the Austro-Hungarian Empire?

I think I’m gonna order a new nut, and see if I can get my MoT retest pushed back a bit.