Assembling competition bump stops for hydro minis

[minstix]

I recently bought a new set of competition bump stops to fit to my MK2 Mini Cooper S which I'm restoring. I don't intend to put the car into competition but it's well known that fitting these to hydrolastic minis helps to reduce the front to back toing and frowing that the cars have been famous for. They also help to take some of the strain from the 50 plus year old displacers which have long become unavailable.

I've had the car a long time and I fitted a set of these bump stops 30 years ago. Now, the old brackets are very rusty and the rubber parts are cracked and perished. So I bought a new set, which are relatively in-expensive and are easily fitted to the car. The kit of parts comes with four metal brackets and four rubber parts, all seperate. It looked all very straight forward. Or so I thought!

The new rubber parts are a different shape compared with the ones I fitted 30 years ago. The old ones are barrel shaped and thinner at the place where you attach them to the bracket. The new ones are bullet shaped with quite thick rubber around the mounting hole. Try as I might, I couldn't get the rubber parts to go onto the metal brackets, even with lots of lubrication. With the bracket in a vice and pushing as hard as I could, there was no chance of them going on. I remember fitting the original versions this way without too much trouble. I may have been a bit stronger 30 years ago but I don't think I was in the King Kong league back then.

I had to come up with a way of fitting them and I came up with a simple home made tool to do the job. Here's a link to a YouTube video I made about it in case anybody else has the same problem.

Steve

https://youtu.be/xCj5SqykkbY

Front competition bump stop installed_Small.jpg

[Peter Laidler]

I fitted these competition bump stops from Somerford Mini to my 69 S and they went on the bracket with just a bit of rubber grease and twisting. The bump stop wasn't the problem. The front brackets were though!

Took a bit of machining to fit properly and align the through-bolt holes at each side. I did tell Somerford that the brackets were total crap but to be absolutely fair, they did offer to change them straight away but I had already corrected the faults and they upped their inspection process too.

I didn't really need comp bump stops but used them as a bit of a precaution against a failing hydro unit. I noticed that the rear comp bump stops just prevented the tyre (4.5" S wheels) from fouling on the wheel arch when the hydro was depressurised

To be honest, I think that these buffers are a good idea for any hydrolastic owner

[mab01uk]

Good solution and great video, many thanks for posting.

It would also be worth adding it to the 'How to' section of the forum for future reference

'Mini Related How To'
How to complete tasks on your car, tips & tricks:-
http://mk1-forum.net/viewforum.php?f=31

[rolesyboy]

Agreed. Great video.

[AndyPen]

Where there is a will there is a way!! Nice one Steve

[whistler]

As Peter said, it's the twisting whilst pushing that sorts this problem.

[BAD942B]

They also help to take some of the strain from the 50 plus year old displacers which have long become unavailable.

We used to fit top shock brackets, adjustable front shocks & modified lower shock bolts aswell 40 + years ago to help the displacers

[Peter Laidler]

Like others who have written about this in the past, never understood the logic of that BAD. Even though some still do it today. It's simply that the hydro units are by definition shockers in their own right and have their own inbuilt valves.

[Spider]

Nice work.

I fit these on the fronts of our Outback Mokes. For a Bump Stop, they really are the bee's knee's.

Those I was fitting up to about 2016-ish, would go together with a good shove, however like Steve, those since around then have been extraordinarily difficult. I've managed with rubber grease and then doing them in the press, even then, they haven't gone easy.

The rubber in these more recent ones is definitely harder.

The rubbers by the way, are the standard rear bump stop from the MGB.

[minstix]

Yes, the rubbers are definitely thicker and firmer than the old barrel shaped versions. I tried pushing, twisting while pushing, pushing harder, squeezing in a vice, swearing at it. I still couldn't get it to go on.

I initially tried red rubber grease, then silicon grease as a lubricant. The instructions suggested brake fluid which I thought would make a great paint stripper on the brackets and I'd soon have rusty brackets again.

Prior to trying to fit the rubbers, I had stripped off the very thin black paint from the brackets that they had come with. Then I primed and then painted them with two coats of a very hard wearing paint from Eastwood. Extreme Chassis Black Satin. I've found it to be very chip resistant once it cures properly, which can take several days. I did wonder if the extra paint thickness was making fitting the rubbers that bit harder but it would add about half a millimetre I'd have thought.

I got mine from the Mini Spares Centre. The front brackets were fine and fitted perfectly. However, I did have an issue with the rear brackets. The mushroom type thing is welded on to the bracket. Presumably there's a hole that the thing sits in and it's welded on from underneath. The problem was that it had left a lump where the weld had been done. This meant it wouldn't sit on the radius arm mount that is part of the radius arm casting so wouldn't sit flat. I had to grind these off flat.

The front pair had already been ground off when they arrived, otherwise there would have been the same problem. I think my rear pair must have missed this process. Anyway, grinding flat on a bench grinder and re-painting solved the problem. Other than that, the holes etc all lined up perfectly.

Steve

Bump stop with weld lump.jpg

[Peter Laidler]

As suggested in another thread. The PERFECT lube for getting these rubbers over the mushroom is KY gel. You'll probably have to borrow the tune from the wife's private drawer!!

[RichB]

Had to tackle this job today. It all looks so improbable!


I simply used a piece of wood with a slot to hold the bracket in place and pulled/twisted the wood as I tightened the vice.

Each one took less than 2 minutes after that.

[whistler]

I used silicone grease but after a short ride with them fitted took them off and fitted standard hydro bump stops. I still have the rear ones fitted so far.

[RichB]

What was the issue with the front ones?

[Peter Laidler]

Not the answer you wanted but I fitted the heavy duty front ones as a precaution........

My suspension went down on my S and the rear tyre rubbed on the rear body and trim. The heavy duty rubbers will prevent this.

I realised that there was room at the front to fit the heavies too......, so I did, as a bit of a precaution against the same event.

The only 'problem' I've found since, is that when depressurising the system to work on it, the heavies hold it up higher than normal! But that's what they are meant to do. So before I work on the system, prior to depressurising it, I simply remove the buffers. Dead simple.

But that's why I've kept my heavies fitted and suggest other S and wider track mini owners do the same.

[whistler]

What was the issue with the front ones?

The new comp one split its rubber so fitted a replacement but the ride was too much like rubber donuts so now I have a much better ride just with hydro. If I need to stop front raising I'll fit a pair of shocks (already fitted top bracket and bottom pin in anticipation). Currently running in down in Spain and suspension is fine just on hydro with rear comp bumpstops.