LCGB Forums

On removing my rear shock I've noticed the threads on the bottom mount are in a very poor state. How easy is it to replace the mount? And are there any tips on the best way to do it? Many thanks in advance.

I’m sorry that you’ve had no response to your request, but I’ll try.

The bottom shock mount is a steel component integral with the engine casing with M16 x 1.5 threads.

It would be good if you could show us a photo of the issue as perhaps any damage might be repairable with care.

As far as I know, the mount is not replaceable BUT many years ago, I had an engine where the mount came loose & it was possible to pull it out! I Loctited it back in after thoroughly cleaning up the mating surfaces.

That may not help you a great deal, but even if your mount is not replaceable, or restorable, there will be other ways of obtaining a secure method of retaining the shock absorber.

I hope this helps.

thats a tricky one.

As it is cast in the aluminium crankcase as an integral part I doubt whether it would be feasible to remove and replace it .

My advice would be to run a insert or helicoil onto the existing thread and weld it on.
You might need to weld a ms tube on the spigot in which case you would then need to have the ring on the shock absorber drilled and reamed to the new spigot size. That would be the cheapest strongest easiest way I think
http://www.theinsertcompany.com/steel_self_threading_inserts.php
http://www.thorintl.com/Drill-Sizes-HeliCoils-Metric.shtml

not a nice job to do i would think, would a thread file not help out?
scooter restos sell them as replacements, odd if they can,t be replaced.
i saw a previous thread that someone suggested cutting off the thread section and drilling /tapping the stub for a bolt and large washer.
or cut a new (smaller) thread with a die and use smaller nut with washer

Restos sell Indian, Spanish and Innocenti NOS versions, agree it would be odd to do so if they weren't replaceable.

I'm sure I read somewhere they could be pressed out?

Hi guys , thanks for the replies. I have seen replacement mounts readily available it's more a matter of how to get the old one out

A picture can paint a thousand words sometimes some things that at first glance look like they can't be repaired but can sometimes it just takes a bit of patience and time it's not al ways expensive.

Quick update. After looking at different options the thread was cut off. The mount was then drilled and tapped to take a stud which was inserted. Job done and good as new. This method was chosen event though replacement mounts can easily be purchased. However, looking at them in more detail it looks like it would be a pain to remove and would require to be pressed into place.

by Stesjh » Wed Jun 29, 2016 11:37 am
Quick update. After looking at different options the thread was cut off. The mount was then drilled and tapped to take a stud which was inserted. Job done and good as new. This method was chosen event though replacement mounts can easily be purchased. However, looking at them in more detail it looks like it would be a pain to remove and would require to be pressed into place.

That is a good fix as long as there is sufficient wall thickness around the M16 x 1.5 stud to ensure enough remaining strength.

Personally, I’d have considered the option of drilling through to suit an M12 screw LH thread & replace the damaged portion that would be secured by the screw. The head of the M12 screw would be on the ‘nearside’ possibly fitting in a counter-bored hole if feasible.

Warkton Tornado No.1 wrote:

by Stesjh » Wed Jun 29, 2016 11:37 am
Quick update. After looking at different options the thread was cut off. The mount was then drilled and tapped to take a stud which was inserted. Job done and good as new. This method was chosen event though replacement mounts can easily be purchased. However, looking at them in more detail it looks like it would be a pain to remove and would require to be pressed into place.

That is a good fix as long as there is sufficient wall thickness around the M16 x 1.5 stud to ensure enough remaining strength.

Personally, I’d have considered the option of drilling through to suit an M12 screw LH thread & replace the damaged portion that would be secured by the screw. The head of the M12 screw would be on the ‘nearside’ possibly fitting in a counter-bored hole if feasible.

All seems to have gone really well, more than enough thickness so fingers crossed to many more miles of scootering

Although you've now done the job, I would have got a shock nut, cut it in half with a hacksaw and fitted each half onto a good area of the threads. You then wind it off with a spanner. This may recover the damaged portion of the threads.