Knock from Front Suspension

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yosini
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Knock from Front Suspension

Post by yosini » Thu Jul 09, 2020 11:15 pm

Hi,

I hope everyone is well. I've had a knock from the front suspension ever since owning my 6a, last years MOT (the first under my ownership) identified one of the front trunions was on its way out so they were both replaced and I thought that would be the fix. Unfortunately not, it carried on knocking, mainly on full lock it would do a clonk type knock, more noticeable at low speeds but that could just be due to it generally being easier to hear. It went in for its MOT again today (early and not even needing one!) and I asked them to check the front, it passed the MOT and apparently everything is 'rock solid and as it should be' at the front. They could hear the knock on a test drive but couldn't find where it was coming from. They are going to have another look tomorrow but I thought I'd see if anyone on here had ever had anything similar.

Thanks in advance

Joe


1963 Daimler Dart
1968 Jensen Interceptor
1969 Rover P6 3500
1972 Maserati Indy
1972 TVR Vixen
1974 Lotus Elan +2 130/5
1977 Scimitar SE6A
1980 VW T25 Campervan
1981 VW T25 Campervan
1988 Toyota Hilux pickup
1996 TVR Cerbera AJP 4.2
1999 Subaru Impreza Turbo Sportswagon
2003 Smart Roadster

rjudcsx
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Knock from Front Suspension

Post by rjudcsx » Thu Jul 09, 2020 11:37 pm

I have a similar situation with my 5a , a clunk / knock from what appears to be the left front suspension area . Like yours audible when I take it out of the drive on medium lock . When I had it on stands I checked the trunnions , spring , shock mounts and could find no apparent problem , no clunks heard when I drive it . I have been wondering about the s/rack mounts [ no pas ] , anti roll bar but as yet have not investigated further . My intuition says I should look at the spring again in its upper and lower pans as I had a similar sound on a MG once and the spring looked ok but had a fracture right at the top of the coil ,which was partly hidden by the upper spring pan . Please post how you get on as it may help me resolve my issue . Regards Richard .



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ScimiTom
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Knock from Front Suspension

Post by ScimiTom » Thu Jul 09, 2020 11:50 pm

I had a similar irregular knocking coming from the offside front whenever I turned a corner. This time last year I had the exhaust downpipe repositioned to allow clearance at the chassis (it was much closer than on the nearside), Copperslip applied to the upper wishbone bush mounts, and the lower trunnion mounting bolt freed up and reassembled. This cured it, but the knock has now returned. I'm about to fit new springs and a new exhaust system, so will see if that sorts it and let you know.

Tom


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rjudcsx
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Knock from Front Suspension

Post by rjudcsx » Fri Jul 10, 2020 12:44 am

Just had a thought , wonder if a split engine mount rubber could portray this symptom . Mine have been changed about 5 years ago when the engine was rebuilt , but you never know . Regards Richard .



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philhoward
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Knock from Front Suspension

Post by philhoward » Fri Jul 10, 2020 5:01 am

Power steering or manual?


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Coupe Racing
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Knock from Front Suspension

Post by Coupe Racing » Fri Jul 10, 2020 7:13 am

Any play in the roll bar link


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JoeySully
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Knock from Front Suspension

Post by JoeySully » Fri Jul 10, 2020 7:22 am

I had a similar problem and it was caused by a cracked lower suspension mount. Was impossible to see without removing the lower arm.



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adamwilkes
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Knock from Front Suspension

Post by adamwilkes » Fri Jul 10, 2020 8:16 am

Sounds like the spring winding up then jumping - maybe your suspension has evolved into a Macpherson strut :lol: :lol:


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yosini
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Knock from Front Suspension

Post by yosini » Fri Jul 10, 2020 7:32 pm

Some good potential reasons here thanks, I hadn't thought it could be a broken/dodgy spring - that's something that wouldn't easily be spotted and would explain why it is pretty noisy over all the speedbumps in London...rollbar link seems fine but might be worth a rebush as this one is a keeper so I'm happy to replace things without strictly needing to. Not sure about the engine mount but the gearbox mount is apparently on its last legs so will change that. It's powered steering.

Thanks again all, and have a good weekend!

Cheers

Joe


1963 Daimler Dart
1968 Jensen Interceptor
1969 Rover P6 3500
1972 Maserati Indy
1972 TVR Vixen
1974 Lotus Elan +2 130/5
1977 Scimitar SE6A
1980 VW T25 Campervan
1981 VW T25 Campervan
1988 Toyota Hilux pickup
1996 TVR Cerbera AJP 4.2
1999 Subaru Impreza Turbo Sportswagon
2003 Smart Roadster

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giddo
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Knock from Front Suspension

Post by giddo » Sat Jul 25, 2020 10:48 pm

I have a very similar set of symptoms on the GTC, MoT tester asked to have serious look - could find no issue.
Only herd when manoeuvring in car parks, ie lock to lock and a dab of the brakes.
I had another car in the past with a fracture in the end turn of a coil spring, invisible until dismantled.
Please report if / when you do find a cause.


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rjudcsx
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Knock from Front Suspension

Post by rjudcsx » Mon Jul 27, 2020 10:54 pm

Any movement on this Joe , the issue not the part :) Regards Richard .



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giddo
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Knock from Front Suspension

Post by giddo » Mon Aug 17, 2020 10:26 pm

My eye has just been caught by re-appearance of this thread, I see 3 years have passed ! In the case of my GTC the occasional knock ( exactly fitting all of the above symptoms ) has just stayed the same but last year the MoT tester decided to note an advisory of " Front road spring distorted" I have 2 new springs on order, expect to fit this week.
I have a cracked or broken spring as top of my suspect list as I have just discovered that the front of the car is nearer the ground than before.
I will try to report back


Mike Giddens
The frog? I live in a village called Frogham
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ScimiTom
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Knock from Front Suspension

Post by ScimiTom » Mon Aug 17, 2020 10:46 pm

After fitting new springs all round and trunnion kits on both sides, the knocking sound on mine has gone. In my case it was the trunnion bolt at fault, but the front springs do have a hard life and should be the first suspects.


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