Technical Front end knock 100hp

[Martinlfb]

Afternoon all
My car has a weird occasional knock that i can feel through the bulkhead, It usually happens on the first application of the brakes and especially if turning at the same time e.g coming up to a junction.

I have had a quick spanner check of all the nuts and bolts I can get to from underneath and nipped up a couple of the subframe bolts but its still doing it.
The car has recently had springs, dampers, top-mounts, droplinks and track rod ends fitted.

Any ideas greatly appreciated.

 

[koalar]

The car has recently had springs, dampers, top-mounts, droplinks and track rod ends fitted.
.

Lower suspension arms
Have they been changed recently. If they were poor quality they can be trashed within a year

Fairly easy to test as it’s always the rear mount the goes first

 

[Martinlfb]

Lower suspension arms
Have they been changed recently. If they were poor quality they can be trashed within a year

Fairly easy to test as it’s always the rear mount the goes first

Done about a year and less than 2000 miles ago. I fitted Magneti Marelli 100hp fitment arms.

 

[koalar]

Have you checked the calliper slide and bracket bolt aren’t loose

 

[koalar]

I have had a quick spanner check of all the nuts and bolts I can get to from underneath and nipped up a couple of the subframe bolts

I am slightly concerned that they could be nipped up

They should be very tight and shouldn’t ever come loose

It is possible to be missing one as per

Front subframe bolt snapped in chassis | FIAT Panda (Mk3)

Hello folks, I’ve been having an intermittent clunking noise coming from my 2004 when I set off and apply torque from the engine, on the right hand-side of the vehicle, it could be felt through the floor of the car. This was ever since a new steering rack was fitted by in March. At first I...

www.fiatforum.com

 

[DaveMcT]

Also check the front strut top bearings and indeed the struts. They can clunk when worn.

 

[Martinlfb]

Thanks for all the suggestions so far. I'll check the last two things.
Does anyone have an exploded diagram of all the front end suspension components that I can use for reference?
Many thanks

 

[koalar]

Click on the pictures at the bottom

44301/00 - FRONT SUSPENSION

FIAT NUOVA PANDA (2003-2009)

eper.fiatforum.com

 

[koalar]

Just had to fix mine for knocking

Tie rods gone. Only a year old

Not saying yours is the same. But just because the parts are fairly new doesn’t mean they can’t be the problem

Cars hit a few pot holes lately and loads of speed humps

 

[bugsymike]

Click on the pictures at the bottom

44301/00 - FRONT SUSPENSION

FIAT NUOVA PANDA (2003-2009)

eper.fiatforum.com

Just a thought, I have had a few other makes of cars where the bottom wishbone bolts have been tight and or seized but not pinching the bushes, so the the wishbone can move under heavy load as in braking etc. but not if you just shake the wheel. If it has gone on for some time it may be possible to see rust stains in that area where it has been working and fragments of metal have come off. You sometimes see similar markings where a road wheel is lose and the wheel works around the nuts/bolts holding it on. It seems to be usually the front mounting bolt on the wishbones that I have seen.

 

[koalar]

Just a thought, I have had a few other makes of cars where the bottom wishbone bolts have been tight and or seized but not pinching the bushes, so the the wishbone can move under heavy load as in braking etc. but not if you just shake the wheel. If it has gone on for some time it may be possible to see rust stains in that area where it has been working and fragments of metal have come off. You sometimes see similar markings where a road wheel is lose and the wheel works around the nuts/bolts holding it on. It seems to be usually the front mounting bolt on the wishbones that I have seen.

Correct

Everything has to be clean

And the parts tightened to the correct torque whilst the car is sitting at the correct ride hight

Otherwise the metal section the lower arm sits in will not pinch together correctly.

 

[bugsymike]

Correct

Everything has to be clean

And the parts tightened to the correct torque whilst the car is sitting at the correct ride hide

Otherwise the metal section the lower arm sits in dose not pinch together correctly.

I am also a fan of wire brushing slightly rusted bolt threads and applying copperslip or oil so the threads don't bind giving a false feeling of being tight. It is especially important on things like "stretch" bolts where if dragging gives false tightening. On things like cylinder heads I would take extra time to clean down every thread hole to make sure the head was bolted down securely, even using an old head bolt ground on my bench grinder to give a "thread tap" effect to collect the dirt from the threads.

 

[DaveMcT]

I use Action Can CS90 on all threads - a high solids anti seize paste. It's much thicker than the usual copper grease. It works extremely well between stainless and aluminium so carbon steel vs aluminium's easy peasy. Some say it should never be used in these situations but my bitter experience has proved them wrong. It simply stops the electrolytic oorrosion process. I don't know how it works (maybe it shorts out the battery effect) but it does the job extremely well. In my opinion, cheap copper grease is too slippery - risking over-tightened bolts. The cheap stuff only gets brushed on for corrosion protection.

The front M8 bolt on my gearbox mounting bracket (dry from the factory) was badly corroded. It's gone back (fully coated in goo) until I can get a replacement, but the crud was frankly shocking. The hole thought the alloy mount has good clearance but that bolt was close to being trashed.

I do not use anti-seize on specialist fasteners like cylinder heads, where the torque setting is critical. Any lubrication is likely to upset the setting leading to over-tightnening so keep them per the instruction book.

 

[DaveMcT]

Regarding the knock - culprits are -

Top mount bearings​

Inner or outer trak rod joints​

Drop links​

The latter are about £15 each from Shop-4-Parts, but be prepared to cut the bottom bolts. Mine just spun and refused to unscrew even with help from vice grip pliers to compress the pin against its taper. I used an angle-grinder & slitting disc to slice the nut across the Nyloc to no avail so had to cut the pin itself.

By the way, this method usually gets the nuts off track-rod ends without damaging the spindle. Cut a diagonal slot across the nut and nyloc top, but be careful. If you go into the threads, you'll need a new joint.

 

[koalar]

I fitted plastic £5 drop links last time similar to this

Early days yet as I only fitted them about a month

Proper ones only lasted just over a year


That not to say this is the original posters problem.

 

[DaveMcT]

Our 1.2 has 85K miles and (probably) the original drop links. We had a rattle and one was getting worn. A new pair just fitted. Time will tell if the rattle has gone.

My 100HP ws bought showing 75K miles. It now has 125K miles and still has the same drops links. Amazingly, I was able to unscrew top and bottom joints on both sides when the (long over-due) new shocks were fitted. But it did need a new track rod end - the second set I have fitted.

 

[koalar]

Our 1.2 has 85K miles and (probably) the original drop links.

My 100HP ws bought showing 75K miles. It now has 125K miles and still has the same drops links.

It’s not milage that kills them

Live near a road with sleeping policemen and parked car so only one side is hitting the humps will put more wear on the drop links in a month of daily use than several years of driving elsewhere

 

[DaveMcT]

Speed bumps in my area tend to affect driver's side (passenger side link was the most worn). But potholes and generally crap roads are everywhere n Devon.

I've not been able to find the stats, but Wikipedia says Devon has more miles of roads than any other county in UK. Many are ancient single tracks with a minimal thickness of tarmac that's (shall we say) less than smooth. Potholes are common and road edges are often broken. Most are sunken lanes with the road surface below the surrounding land. Stone walls lurk on either side hidden by soft looking vegetation. If you see a pot-hole its probably impossible to avoid. Road verge holes are more likely that tyre track areas but you just never know. Max safe speed is around 20mph but pot holes really don't care about such trivia.

The 155-80-R13 tyre is a good bet for any Panda in Devon. Though a 175-14 inch with appropriate side ratio would handle better where you can use the car's F1 performance.

 

[Martinlfb]

I spanner-checked everything a few weeks ago an now the knock has gone!
I nipped up everything but I think it was the bottom caliper carrier bolt as that felt slightly loose!

Thanks for you everyone's help.

 

[bugsymike]

I use Action Can CS90 on all threads - a high solids anti seize paste. It's much thicker than the usual copper grease. It works extremely well between stainless and aluminium so carbon steel vs aluminium's easy peasy. Some say it should never be used in these situations but my bitter experience has proved them wrong. It simply stops the electrolytic oorrosion process. I don't know how it works (maybe it shorts out the battery effect) but it does the job extremely well. In my opinion, cheap copper grease is too slippery - risking over-tightened bolts. The cheap stuff only gets brushed on for corrosion protection.

The front M8 bolt on my gearbox mounting bracket (dry from the factory) was badly corroded. It's gone back (fully coated in goo) until I can get a replacement, but the crud was frankly shocking. The hole thought the alloy mount has good clearance but that bolt was close to being trashed.

I do not use anti-seize on specialist fasteners like cylinder heads, where the torque setting is critical. Any lubrication is likely to upset the setting leading to over-tightnening so keep them per the instruction book.

Re not using anti seize on head bolts , some are supplied with a satchet of anti seize grease.
I like to make sure threads are free and easy, as I have seen some stretch bolts actually springing against the torque wrench before they have pinched up the cylinder block threads, so no way are they pinching down correctly.
I was not talking about swamping the thread so it hydraulically locks, just a small dab after cleaning the thread holes and running the new bolts all the way down once before final assembly and a little on the washer end.
At the end of the day do what works for you, 50 years and no "come back jobs" and all regular customers