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Reducing bolt hole size. Possible?
dan8400 - 20/8/15 at 04:28 PM

Hi everyone

I am looking at changing my rear shock absorbers. The ones I have now are from a Peugeot 205 and I'm looking to replace with classic mini items (the car should have had these from the start (tiger supercat)).

Problem is, the 205 shocks have a 16mm bolt through them (so holes enlarged on chassis) and the mini times are 10mm (I think?)

Is there a way I can reduce the bolt hole size in the chassis? Is there some kind of washer I can use as like a sleeve?

Sorry I don't know the technical terms (if such a thing exists)

Thanks
Dan

OliilO - 20/8/15 at 04:39 PM

A top hat spacer/washer might do it.

dan8400 - 20/8/15 at 04:41 PM

Ok. Thank you for the reply. Do you have a link?

Thanks
Dan

OliilO - 20/8/15 at 04:43 PM

https://www.google.co.uk/#q=top+hat+spacers

joneh - 20/8/15 at 04:46 PM

On suspension I'd get the brackets remade.

I reckon a plastic top hat would wear out fairly quickly unless you can get them in steel.

dan8400 - 20/8/15 at 04:48 PM

Thanks Joneh. I was looking for steel ones. If the only choice is plastic I'll do as you suggest and get new brackets welded on

Thanks
Dan

dan8400 - 20/8/15 at 05:13 PM

Can I get someone to weld in some thick penny washers at the right size? Or is this dodgy?

40inches - 20/8/15 at 05:27 PM

Something like this?

dan8400 - 20/8/15 at 05:30 PM

That's the kind of thing. I need it 16mm down to 10mm. Had a Google. Couldn't find anything yet. Might just get the brackets re done.

Thanks for the replies anyway guys

Thanks
Dan

rusty nuts - 20/8/15 at 05:36 PM

The holes for the Mini shock absorbers are likely to be 3/8" not 10mm

dan8400 - 20/8/15 at 05:38 PM

Thanks rusty

joneh - 20/8/15 at 05:41 PM

Those look nice. As he ^ says classic mini shock bolt size is 3/8.

[Edited on 20/8/15 by joneh]

cliftyhanger - 20/8/15 at 06:55 PM

You may be able to get polybush with correct outer and inner sizes? As in replace the bushes totally.

joneh - 20/8/15 at 07:29 PM

quote:
Originally posted by cliftyhanger
You may be able to get polybush with correct outer and inner sizes? As in replace the bushes totally.


It's the chassis that's too big, this would need the shock reamed but I doubt there would be enough material.

Theshed - 20/8/15 at 08:05 PM

This is a simple lathe job to make up some top hat spacers. I might be able to do these for you but am usually trampled by loads of folk on here with a lathe

dan8400 - 20/8/15 at 08:32 PM

Wow that's a generous offer thank you. I promise I won't trample on you! What sort of cost do you think?

I will need 8 in total. Outer size 16mm inner size 3/8. I will double check though.

Thanks
Dan

Theshed - 21/8/15 at 05:59 AM

Ok I can make you some top hat bushes to suit the holes. A sketch would help. How thick and how wide a "brim". I think I have a 3/8 reamer. Are you sure 16mm is not actually 5/8"?

What material would you like? Mild steel should be fine but I do have much more exotic stuff.

Cost - pass on a favour

Time scale - I could do this on the weekend

cliftyhanger - 21/8/15 at 06:12 AM

quote:
Originally posted by joneh
quote:
Originally posted by cliftyhanger
You may be able to get polybush with correct outer and inner sizes? As in replace the bushes totally.


It's the chassis that's too big, this would need the shock reamed but I doubt there would be enough material.


I know the mini shocks have been used on other cars by changing the bushes. I very much doubt the "eye" or bush holder on the mini shock is anything like as small as 16mm. Or are you getting them with spherical bushes? in which case speak to the manufacturer.

jeffw - 21/8/15 at 06:45 AM

Did Tiger really use Mini shocks on this kit?

dan8400 - 21/8/15 at 06:52 AM

Hi clifty,

Don't take this he wrong way but have you read my OP? Kind of explains it.

Theshed,

Thank you so much. I will measure and sketch as soon as I get home. Please let me pay you something. I don't wan t you to be out of pocket.

Jeffw,

Yes they did. You could upgrade to Spax items but I didn't. I was on a budget then and I am now. Wish I had more cash but that's how it is I'm afraid

Thanks everyone
Dan

Slimy38 - 21/8/15 at 07:38 AM

I would go for getting the holes filled in with welded discs of the same thickness, then redrill to the correct size.

Charlie_Zetec - 21/8/15 at 09:24 AM

quote:
Originally posted by Slimy38
I would go for getting the holes filled in with welded discs of the same thickness, then redrill to the correct size.


May be the cynic in me, but not sure I'd want my suspension relying on such a small welded area on repeat strain perpendicular to it. If it were me, I would speak to local machine shop (or someone with a lathe) and get some top hat washers made up for BOTH sides of the current mount, thus spreading the load better.

Land Rover Defenders use a similar design for the top of their shock absorbers and upper & lower on the front, but I don't think the hole size is reduced by 6mm; more like 2. But at least you know it has/can be done!

britishtrident - 21/8/15 at 10:23 AM

Once tightened up the location is provided by friction between the ends of the inner tube of the bush and the bracket.
To do this the end tube has to have a decent annular bearing area on the bracket.

Only real solutions to this are (1) New brackets or (2) Special bushes.

A skilled gas welder could probably do something but doing it on the car really isn't on.

Keep in mid also the Mini dampers were designed for cars with rubber suspension, a lot of the damping came from the natural hysteresis of the rubber cone.

ISTR the bolts on Mini dampers were most likely to be 7/16" dia approx 11mm

[Edited on 21/8/15 by britishtrident]

[Edited on 21/8/15 by britishtrident]

Theshed - 21/8/15 at 01:11 PM

Lets have a picture then and the collective can design the best bushes and I will turn them up. There really should not be much sideways load on a shock mounting.

dan8400 - 21/8/15 at 01:15 PM

I may just stick with the 205 units. Not worth an arguement

cliftyhanger - 21/8/15 at 05:12 PM

quote:
Originally posted by dan8400
Hi clifty,

Don't take this he wrong way but have you read my OP? Kind of explains it.


Yes, I read it. You have 16mm holes in the chassis to mount the shocks, but the bushes in the mini shocks use (probably) 3/8 or similar bolt.

people use mini shocks on some Triumph GT6's, they use a large shouldered bolt, guessing 5/8 which is essentially 16mm. They use a special bush, or possibly the std GT6 or spitfire bush.

However, if the tophat washer is a go-er, do it. I was merely suggesting an alternative way to skin the proverbial cat.

dan8400 - 21/8/15 at 05:57 PM

Thanks for that info clifty. I wasn't trying to be a dick about it. Hope it didn't come off that way


Thanks
Dan

dan8400 - 28/8/15 at 04:41 PM

Hi Theshed,

If your offer is still open I would love to take you up on it. I have made a sketch, literally on the back of an envelope. I hope it makes sense.


I would like 8 bushes in total if possible. I will gladly pay you for your services if required




Thanks
Dan

yellowcab - 28/8/15 at 10:21 PM

quote:
Originally posted by Theshed
Cost - pass on a favour
Theshed - what a gent!

RoyM - 29/8/15 at 06:13 AM

Wheel but spacers / reducers? Got some on my Marcos minilites which are 3/8 bore - may save you finding a lathe

Theshed - 29/8/15 at 02:30 PM

Hi

Sorry I did not spot this yesterday. Sure I can do those for you. I am away for the weekend but will be able to do them probably before next weekend - is that OK?

Few questions. You have not shown the diameter of the bar. What would you like. I have stacks of 34mm mild steel bar I can turn down. I could do bigger or smaller.

Are you sure about the 10mm hole a 3/8 bolt is just over 9.5 and will rattle a bit in a 10mm hole. I can do either or send you a sample pair. I generally use imperial bolts and have lots lying around. What size (length) will you need to go right through?

If your hole is exactly 16mm and I make these exactly 16mm you will need a sort of press fit. You could draw them in with bolts or file a sliver off the hole. Or I could make them a thou undersized and they will be a sliding fit. What is your preference?

All the best

dan8400 - 29/8/15 at 04:55 PM

Hi,

Thanks for the reply. 10mm is perfect as I have enlarged the holes in the shocks to 10mm. Not fussed about the outside diameter of the bar. Anything is fine.

Also, whenever you can do it is fine. Next weekend is fine by me.

16mm will fit. 16.5 may be better. I can file it if it's tight.

Total length of the bolts will need to be 75mm x m10. I can get bolts, nuts and washers.

If you need more info I can provide it

Thank you once again
Dan

[Edited on 29/8/15 by dan8400]

Theshed - 5/9/15 at 03:34 PM

And the lathe fairy spat these out.....

Napkin design
Napkin design

In the post on Monday

dan8400 - 12/9/15 at 08:54 PM

Just wanted to take the time to say a massive THANK YOU to John 'theshed' for making me the bushes I needed for my suspension.

They are brilliant. Really high quality work. Unfortunately I seem to be incapable with my tape measure and ended up making them a little smaller to fit. The turned part sat in the hole I was trying to fill and the new bolts fitted effortlessly into place. I have included a picture below to show Johns quality parts fitted to my car

Thank you John!!



Thanks
Dan