Sudden front suspension drop

toddao · Post by **toddao** » Fri Oct 09, 2009 7:15 pm

When I switch off the engine, the front suddenly drops about twenty cms or so with a hissing sound and there it stays, not sinking any further. I had a bit of a search in 'technical' but I didn't turn up anything specific.
Any thoughts appreciated.

Thankyou

Dollywobbler · Post by **Dollywobbler** » Fri Oct 09, 2009 7:41 pm

Any leaks? When mine was leaking, it made a hissing sound as it sprayed LHM on the ground!

toddao · Post by **toddao** » Fri Oct 09, 2009 8:05 pm

No leaks, just hissing!

MULLEY · Post by **MULLEY** » Fri Oct 09, 2009 8:34 pm

Worn front struts i reckon. If they pump up to the normal height, then i wouldnt worry too much in the short term, but might be worth making sure you have a couple of spare one's knocking about before one of them blows. Had that happen to me on the way to work, although it never did any dropping as you've described, it was clonking though, are yours totally silent when driving?

citronut · Post by **citronut** » Sat Oct 10, 2009 8:20 am

dose it do this before you get out of the car or just after, if the later it is because as you get out the suspension will go up a certain amount then re/settle down to its corect hight

regards malcolm

toddao · Post by **toddao** » Sun Oct 11, 2009 11:32 am

Thankyou for your replies. Nothing serious then? I suppose I'll just live with it if it isn't leaking and the ride is still satisfactory.

Post by **Tim Leech** » Sun Oct 11, 2009 6:54 pm

My GT and TRS does the same todd, when I get out it rises up then falls again and hisses as it does it but performs normally. I wouldnt worry.

cauchoiskev · Post by **cauchoiskev** » Tue Oct 13, 2009 6:09 pm

I would have thought a 20cm drop would take you down to the stops...

Is the pump constantly working todd ? Have you had a look at the leakage returns ?

Aerodynamica · Post by **Aerodynamica** » Tue Oct 13, 2009 9:26 pm

cauchoiskev wrote:I would have thought a 20cm drop would take you down to the stops...

Is the pump constantly working todd ? Have you had a look at the leakage returns ?

- this is what I thought too!

So after it does this drop thing is there any height left in the suspension or is it fully slammed at the front.

If it's the former (i.e. there is still suspension travel left ) then it's good news as it's simply the self levelling working (very) well.

If it's the latter though then suspect a failed strut. My old BX14E suffered a failed strut and would fall at the front in 5 seconds only for the thing to pump back up with the engine running - it would fall again and repeat the cycle until the return pipes blew off and then the LHM did spew forth

toddao · Post by **toddao** » Wed Oct 14, 2009 1:05 pm

Well, maybe 20cms is too much for what it travels as it doesn't go on the stops. Perhaps it's less than that then, just seems a lot when it suddenly drops!
Yesterday it didn't do it at all. I don't know about the struts really. Obviously they're twenty five years old but they've only travelled a mere 50,000 miles - or is that irrelevant?

MULLEY · Post by **MULLEY** » Wed Oct 14, 2009 1:09 pm

I suspect its just age related wear & tear rather than mileage, the seals i guess will disintegrate, shrink/expand etc...You could always try some hydraflush to see if its just gunk/crap in the system, that may help a bit??

Aerodynamica · Post by **Aerodynamica** » Wed Oct 14, 2009 6:57 pm

toddao wrote:Well, maybe 20cms is too much for what it travels as it doesn't go on the stops. Perhaps it's less than that then, just seems a lot when it suddenly drops!
Yesterday it didn't do it at all. I don't know about the struts really. Obviously they're twenty five years old but they've only travelled a mere 50,000 miles - or is that irrelevant?

I think it's simply that the front suspension did its self levelling action. Mostly you don't see it do this as the front end is less prone to height changes with only one person getting out but if 2 or more passengers get out it'll rise up enough to cause the front leveller to lower it back. Also common if you've just made a slow speed full lock move and left the car parked with full lock - it seems to wedge the tyres giving extra upwards push that makes it jump up high when you step out - again causes the self leveller to lower it down.

I think Mk1s are more prone to this anyway due to the roller bearings of the lower front suspension arms but not sure.

So me thinx all is well with your car