Technical Front suspenspion knock

[Ralf S.]

I'm getting a knock on occasion when I'm turning the steering at low speeds. It sounds like it's coming from the nearside (left) suspension top mount.

Since I'm a bit skint at the moment (too many nights out in Ibiza, the MasterCard geezers after my crown jewels and the Younger Mrs S' Cinquecento needing some welding for its MOT etc.) I plan to swap only the worn out part... just to keep me going until I can change the entire damper and mounts etc. when the dampers pack up.

I can see two "hats" on top of the damper. One which is flat .. more like a beret and another one which goes on top of it.

The flat one doesn't seem to consist of much (metal plate with a bonded rubber bush?) whereas the top one looks more sophisticated (and likely to go wrong).

If I replace just the top hat, would that be a good punt, or is it probably best to swap the two together? I think I've talked myself into the latter... but always interesting to hear what people thinks.


Ralf S.

 

[dtimmins1985]

I'm getting a knock on occasion when I'm turning the steering at low speeds. It sounds like it's coming from the nearside (left) suspension top mount.

Since I'm a bit skint at the moment (too many nights out in Ibiza, the MasterCard geezers after my crown jewels and the Younger Mrs S' Cinquecento needing some welding for its MOT etc.) I plan to swap only the worn out part... just to keep me going until I can change the entire damper and mounts etc. when the dampers pack up.

I can see two "hats" on top of the damper. One which is flat .. more like a beret and another one which goes on top of it.

The flat one doesn't seem to consist of much (metal plate with a bonded rubber bush?) whereas the top one looks more sophisticated (and likely to go wrong).

If I replace just the top hat, would that be a good punt, or is it probably best to swap the two together? I think I've talked myself into the latter... but always interesting to hear what people thinks.


Ralf S.

Sounds like you have described the top mounts.
It comes in two parts as you describe.

Bit weird that your hearing knocking when turning though, that sounds more like a C.V joint or something that's loose.

The top mounts on the suspension dampers (the very two last parts you assemble when building up the shock / spring just before you put the top mount nut on, then hoist her up into the wing)...

Well, they dont usually knock, they creak more than anything, my silver stilo had an impact on the drivers side, i replaced lots of bits but the garage left the old top mount and fitted it to the new shock - what a dick... about 1 week later, the nice smooth and quiet car was now squeaking and creaking when i turned the steering wheel and went over bumps, not knocking though.

I replaced the top mount (both parts) and it was fine after.

I will say though, the blue multijet (Daniella) that just left me... well - i replaced the whole front suspension on that motor but left the top mounts, they looked visibly fine, all i did was blow them out with the air line then soaked them in brake cleaner, blew them out again and injected some landrover grease into tiny openings i could see (where the bearings of some sort sit) - it was fine for over 7 months and had no noises.

I wouldn't buy just the top hat as you call it, double check it all, nip everything up - the very top point should not be loose.

Failing all that, check drops links, track rods and C.Vs, also the front shafts too (they can cause play in the spider cups, but saying that, you replaced them didnt you).

Anyhow - keep us posted but.

Kind regards,
Dan

 

[Ralf S.]

The beast is due an oil change/filter, so I'll have a peek at the suspension when I service it this weekend (I might take out the EGR plates too, what with the MOT coming up and only 1.46 on emissions last time.. plate says 1.34 )

It could well be the driveshaft.. although they've been not bad since I replaced the spiders on each one. The offside cup was slightly chewed up where the old spider fell apart/lost one of its rings and all the needle bearings which then got ground into dust... ) but the offside was only slightly worn. Longer term... complete new driveshafts/CVs won't be a bad idea... but let's see if the beast can pass that new style MOT emissions first...

The knock (clonk?) seems to come from the top of the damper.. but I suppose it could be transmitting up the damper rather than being caused by it.

I already have some Track Rods since neither of them looked great when I changed the spiders and I'll probably fit those this weekend too. The drop links looked fine but I'll check those too.

I'd bet more on the Track Rods .. but I can't make them clonk just turning the steering wheel quickly or slowly. It usually only clonks when the suspension is "stretched", such as over a hump-back bridge, or reversing with the wheel turned right.. something's happening when the suspension is at full extension.

Meanwhile it may be not a bad idea to start building up some new dampers off the car, in my own time... then just fit them as/when/if the OE kit packs up. It's all Fiat as fitted in the factory in 2003 so can't last much longer (although just the dust boots rotted off the bump-stops.. seems in good nick otherwise).

I can find most of the parts; dampers, springs and bushes etc... but what's number 11 in the picture? Is it the original spec' spring catcher? It's just called 50700529 - RING in ePer.

Mine has the "recall" (?) spring retainers - 51792950 - fitted. Do I also need 50700529 (and who sells them apart from Fiat)?


Ralf S.

 

[Davren]

what's number 11 in the picture? Is it the original spec' spring catcher?

Item 11 is a shaped rubber insulating ring. It goes between the bottom of the spring and the spring mounting plate that's welded on the shock absorber.
.

 

[Ralf S.]

That's interesting... I can't see anything between my spring and the damper plate... but I'll have a proper look when the wheel's off.

They're silly money though... does anyone else make them (no joy on eBay etc.)?

I was hoping to build up a new pair of shocks from all new parts and then fit them when I'm ready... but if I have to re-use the rubber doodah it means I'll have to dismantle the old shocks before I can assemble the new ones. Unless I fork out the wedge (cost more than the springs) for new Fiat ones.

Ralf S.

 

[Davren]

That's interesting... I can't see anything between my spring and the damper plate... but I'll have a proper look when the wheel's off.

They are quite difficult to see when fitted and covered with dust. You should be able to feel the rubber though, if it's there.
.

 

[Ralf S.]

Well.. I had a poke about.

The suspension strut has seen better days for sure but it's not bad. There's a miniscule amount of side-to-side play in it and the dust gaiter has rotted off the bump stop, and has dropped onto the spring pan .. but otherwise it's remarkably good for 14 years old.

Meanwhile I put new Track Rod Ends on the beast since the nearside one in particular was a bit ropey but again not bad. The steering feels marginally crisper now so probably just about worth the trouble...

The "clunk" still remains though.

I noticed the n/s driveshaft seems to have a fair bit of side-to-side slop.. maybe 2-4 mm of movement... but if I move it by hand, it definitely moves and if makes a clunk. The o/s driveshaft moves one-third as much.. barely at all ... and doesn't clonk.

The movement seems to be the spider into the cup (inner CV) ... as if the hub nut is loose (it isn't)... but that's strange since the wishbone and the damper should triangulate/fix the hub in position, which should prevent the spider from moving in the cup.

The spider is new so I think it's in the clear. Something is just allowing it to move.

My money is still on the damper since the hub would rotate outwards on the wishbone knuckle anyway, whereas the only thing preventing it tipping outwards (going towards negative camber) is the strut... (?) but someone who knoes more might have a different opinion..


Ralf S.