9 replies to this topic

[ratchet63]

I have had a browse around for solutions / suggestions but couldn't find a solution so here's a new post .....

 

Needed a new back box and "over the rear axle" section for my car.

 

Was (initially) delighted with my purchase of ..... see attached.

 

Came with silencer and next part of exhaust , 2 clamps and a hanger,

 

BUT .... exhaust "clunks" when going over every slightest bump in the road.

 

I have removed and refitted and there seems to be plenty of clearance above rear axle. (I am pretty sure that this is where the clunk is coming from)

 

So now I suspect rubber hangers. I count 3. Back two seem to be quite meaty - about an inch thick - but front one is thin , about 10mm.

 

I have tried brand new one in centre, but exhaust clunks.

 

Have swapped  a thick one to the front but this hasn't fixed the clunk.

 

Alignment of exhaust seems right, hangers are not stretched  

 

Where am I going wrong?

 

Have I bought cheap (again) , and now need to buy twice?

 

 

 

 

[mondy zetecs]

Which part of exhaust is actually knocking,have you matched new part next to old,

if pipe need adjusting cut it and join with connector sleeve.

 https://www.ebay.co....WsAAOSwezVWzE2g

[ratchet63]

I am 80% sure that it is at the highest point of the exhaust where is goes over the rear axle.

New parts seem to fit perfectly so no need for connector.

 

There seems to be plenty of clearance.

So now I suspect the rubber hanging mounts - should the front one be thin (10mm) and the back two fatter (25mm) ? That is my current question I guess.

[mondy zetecs]

Grab the end of exhaust and give it a good rocking should simulate a bump in the road.

My middle or front rubber hangs loose looks thin stretched.

Might be coincidental knock has appeared after doing exhaust and its something else.

Hard to pinpoint knocking,took me over 6 months to identify my knocks.  

Edited by mondy zetecs, 27 July 2020 - 01:15 PM.

[ratchet63]

"Hard to pinpoint knocking,took me over 6 months to identify my knocks.  "

 

Where was your knock and how did you fix it in the end - new rubbers?

[mondy zetecs]

Mine was suspension strut testing 4 corners was a lot more work,but i tested the exhaust just in case,

the point i was making it might be something else that sounds like the exhaust knocking. 

After testing parts and not finding anything i resorted back to the expensive blanket part changing method.

Edited by mondy zetecs, 27 July 2020 - 02:36 PM.

[mondy zetecs]

What i've done in the past to test the exhaust knocking (not recommended) is wet a old jumper, 

tie it round where i suspect its knocking and go for a very short drive over the bumps to prove

or eliminate its the exhaust.(get a bucket water or extinguisher ready)

Edited by mondy zetecs, 27 July 2020 - 04:18 PM.

[hardy1812]

Could it be that it’s too high and hitting the underside or the car ??? Also mine used to actually hit the bumper cutout rather than the frame

[ratchet63]

Mine was suspension strut testing 4 corners was a lot more work,but i tested the exhaust just in case,

the point i was making it might be something else that sounds like the exhaust knocking. 

After testing parts and not finding anything i resorted back to the expensive blanket part changing method.

Thanks Harry,

 

Turns out was anti-roll bar link making the clunk - typically it was the one near the back of the exhaust. Have now replaced both links. So now car is "clunk-free" 

[mondy zetecs]

Glad you got sorted without spending too much,first time i got clunk convinced it was rear

after changing what i could on rear 'expensive' turned out it was front droplink less than £12

aaarrgh!