23 replies to this topic

[nicklouse]

 

 

Damper length controls ultimate droop of the suspension.  There are different spec dampers for lowered cars.

 

I suspect your dampers are standard length and they are bottoming out.  Raising the suspension will help.

 

Thanks everyone for the advice.

Yes so the car has effectively been lowered and I am using standard length dampers. With all those passengers it seems possible that the dampers are bottoming-out when I hit a bump.

I will check and reset the car to standard height at the weekend. Hopefully that will do the trick but I'll monitor the situation.

 

Ah, since it has been lowered, then it would more than likely be the dampers bottoming out.

Some will take this OK and others it can damage them internally.

Shorter shocks should sort it.
 

 

Mmmmmm in my investigations over the years I found that the top of the shocks did not change. The bump stop was in the same place so as to stop the wheel from contacting the edge of the wheel housing/body. So while the stroke was changed the max compressed point was the same. As defined by the top mount and the bump stop.

 

images of a non standard shock to kinda of show what I mean.

 

Shock open.

 

shock closed.

this does not change (much).

the body length tends to be the same all that changes is the stroke. 
start point, droop, changes but bump is the same.

[Spider]

That is interesting Nick.

The shorter shocks I've had (and looked at) where shorter all round, in Extension and compression, granted, I haven't looked at any for several years now.

Checking the published data (when you can find it !!) usually lists the lengths.

[Spider]

Granted, not everyone's favorite, but one example;-

Standard;-

http://www.minispare...px|Back to shop

 

Shortened;-

http://www.minispare...px|Back to shop
 

Likewise, Spax;-

http://www.minispare...px|Back to shop

 

Given shortened shocks are a non-standard part, I'm sure there'll be all many of ways in which these are supplied, including as you've pointed out Nick, shorter stroke types.

[Richard_]

I only mean it's effectively been lowered by fitting new springs then setting the car level on the hilos. Now it's settled it's probably low. But I'll check at the weekend.

[GraemeC]

The ‘lowered’ shocks I’ve used were physically shorter when fully compressed, but I can remember what make they were.

Richard_ - even when you initially set the hilos you were probably effectively lowered by a good 1”. Standard ride height is much higher than people imagine (or generally like the look of), just check out some of the original press photos etc on the internet.

[Earwax]

Just as a note of another thing to check while you are down that way

 

Try to rattle both shocks whilst unloaded.

 

Some aftermarket shocks come with a half nut on the top fixing ( not a nyloc)........quick eyeball for the right hand one, but the passenger one behind the fuel tank may need the fuel tank strap loosened or removed if you can't get a view or feel of it.

(if the nut has backed off it can give you up to a half inch of slap as the damper moves or in the worst case ( which you would have seen) is the piston has come out of the hole....

[ThermalEvent]

Are you using the standard brake lines on the rear which which go through the riveted mounting hole on top of the arm for the brake banjo?

Could it be this mounting plate contacting the body? I've used the following and cable tied to the arms.

http://www.minispare...|Back to search

I'm using GAZ lowered dampers and the rear left knocks over all bumps big or small but everything is OK (had the fuel tank out twice and triple checked everything). Can only put it down to the damper itself and read online others have also had this issue.

[Richard_]

Well I had a look at the hilos today. There was about 1/4" or 6mm free play with the hubs fully down. This doesn't seem right and I'm pretty sure this is the root cause of the issue . With the car too low the shocks were being compressed and running out of travel on major bumps with 3 passengers. I don't know whether the bump stop discs are present in the back of the springs. The stops (or lack of) could also be the bang I'm hearing but less likely I would think.
I adjusted the hilos up a few turns so that there was no free play with the arms fully down.
The ride height came up 30mm both sides as a result. Seems to me there is no real data for factory height setting but the car looks to be sitting ok to me.
We'll see how that goes and I'll check again in a few weeks and periodically after that.

Edited by Richard_, 20 June 2022 - 12:10 PM.

[Richard_]

As a footnote in case some people might find it interesting here are two images I found from official mini sales brochures.

On the left 1989 and on the right 1990 showing some variation in ride height:

 

 

Its not particularly scientific as the camera level is slightly lower for the right hand image, but the car on the right looks set considerably higher to me- if you look at the space above the tyres both front and back.

Maybe the left hand car was driven around a bit more before arriving at the studio.

 

My car currently sits somewhere between the two I'd say so I'm happy with that.

Edited by Richard_, 23 June 2022 - 11:29 AM.