Knocking noise diagnoses help please.

sbcb · 02-11-2009, 02:14 PM

Gidday all I would really appreciate some technical feedback.

Car AU1 V8 Ghia IRS 130,000km
Recently had rear lower control arm bush repalced R side
New KYB gas shocks installed (1 week ago) Upper shock mounts appear good.

and just now replacement rotors and pads all round (stock brake setup - used brembo rotors and bendix pads).

Had a lot of trouble getting the rear discs off and bent a handbrake pad clip in the process (not broken though).

Since the rear brakes have been done have had a rear end knock (appears to be the L side) at low speed (0-50kph then nothing after that speed). Its a constant knock, knock, knock. Applying brakes doesn't affect the knock and no vibration can be felt through the car or pedal. Shifting the car into neutral to coast doesn't affect the knock.
* Pulling the handbrake up gently makes the noise disappear while coasting, then returns the instant you release it.
Hub/disc and alloy surfaces appear clean flat and well secured. Alloy nuts are tighten enough (though not touque checked).

I have just taken the L side rear disc off again, cleaned and checked everything and bent the Handbrake pad clip down further (the pad still has a slight 1mm play in it from alloy to hub, Does it need to hold the pad firm against the hub?) I didn't see any signs of wear of anything rubbing or knocking).
Test drove it around the block after this and it was gone (rejoice!) used brakes a few times, checked handbrake was holding - all good).
Just went into town (12km cruise) while slowing down it was back again (knock, knock, knock, @#$? it).
It is slightly speed related (the speed of the knock) but doen't seem to be being happening as fast as the wheels would be rotating, and isn't going hard out at the 50kph mark, just slightly faster than 10-20kph.

Posibilties
- Handbrake pad causing issue somehow & pulling it on while coasting tightens it up.
- New disc slighlty warped and as it heats up causes knock
- axel, diff got upset when the old disc was getting belted for being stubborn (though I thought these problems wouldn't be so intermittent and the slip into neutral and coast doesn't affect it at all).
- bearing
- radio not loud enough

Any thoughts would be greatly appreciated team.

Gunna sleep on it tonight and give it the fresh perspective tomorrow, I don't see how a little 1mm play in a handbrake pad is responsible for this solid sounding knock.

Carl

:

GK · 02-11-2009, 02:52 PM

Could simply be the handbrake pads hitting inside the rear hub. They usually make a squeaking noise, but perhaps they're hitting a bit hard.

Perhaps take off the offending wheel, and back off the handbrake a little at that wheel.

They can be a pain to get right, but many here have had varying degrees of success getting this noise to go away.

Some pics to give you a guide:

Filing the handbrake shoes
http://www.fordforums.com.au/showpos...2&postcount=68

BTW, the handbrake clip you bent. Is it on the side with the new noise? If so, it may just need a little rebending or replacing.

All the best with it.

GK

sbcb · 02-11-2009, 04:45 PM

Awesome GK thanks for the reply, yes the noise is from the bent clip side.
The wife just took the car into town and it knocked all around town. She pulled into our drive after a cruise home (12km open road little brakes required) I jumped straight in and it wouldn't do it at all. Parked the car up for 15min then took it for another drive and as I came into town (plenty of brake use) it was back. It definitely looks like the L side, definitely handbrake related (its starting to make more noise scuffing and squeaks also) and seems to be that after a bit of brake use the heat causes it to start the knocking. Still seems odd to have this knock from the handbrake but it stops the knock every time I pull the handbrake up gently while coasting.
Cheers again.

mik · 02-11-2009, 09:19 PM

hand brake adjusted tight enough? whell nuts loose? pad knock? hub nut loose? there is a 10 mm hand brake adjustment just at the base of the handbrake handle, if the hand brake is comeing up too far it might need a tighten, or perhaps the hand brake clip you mentioned is too loose, it needs too be firmly down on the lining.

GK · 02-11-2009, 11:14 PM

Mik has also given a good list to work though.

Let us know what it is, and how you go with it.

Cheers,

GK

sbcb · 03-11-2009, 06:11 AM

Cheers guys, I'll try and get to the clip today, I'll have to take the pad off to bend it back enough to make it tight against the hub.

sbcb · 04-11-2009, 06:30 AM

Sorted, pulled the handbrake shoe off and manage to bend the retaining clip back down (slipped a nail behind the inner part of the clip and folded the clip down over it, then took nail out). Holds the shoe firm against the hub now and the knock is gone (touch wood) but hasn't shown any signs in 3 good drives now. Still amazed such a little amount of play could create this noise. Also attacked the handbrake pad as per GK's thread - by the way GK was removing the edges the curer of any squeaky brakes?
Cheers guys for the responses, really helps out.
Carl

frd906 · 04-11-2009, 10:07 PM

i have the same problem now, after i got my car back from suspension work, it has developed a knocking noise on the front left hand side,

when i turn a corner or go over humps and bumps it keeps making a knocking noise any ideas would be very helpfull as i am getting sick of it

cheers

ronwest · 04-11-2009, 10:38 PM

Quote:

Originally Posted by frd906

i have the same problem now, after i got my car back from suspension work, it has developed a knocking noise on the front left hand side,

when i turn a corner or go over humps and bumps it keeps making a knocking noise any ideas would be very helpfull as i am getting sick of it

cheers

Thanks for the spell checker... much easier to read ;)

For starters I would jack that side up and remove the wheel. Then I'd check every nut and bolt in and around the suspension.

Wouldn't be the first time a workshop left a bolt out, or loose.

If all is good at least that will give you peace of mind whilst you're sorting it out.

frd906 · 04-11-2009, 10:42 PM

it went back today to get sorted out, they couldnt find anyting wrong with it, they tightend up my steering rack and said it should fix it, soon as i drove it from acaia ridge in sunny bank, it is getting worse,

im seeing my mech on tommoro after noon or friday morning, he reckons could be my sway bar bushes or my ball joints

ronwest · 04-11-2009, 10:50 PM

Being safe to drive is the main thing, so at least that's ok.
It shouldn't be a real problem for them to sort it out from here.

Good luck with it.

frd906 · 04-11-2009, 10:58 PM

thanks, might pull it off in the morning and have a look,

its my father mechanic in sunny bank, glenn vine auto, who did it,

so should get sorted by the weekend,

cars i tell you, pain in the ***

GK · 05-11-2009, 06:22 AM

Quote:

Originally Posted by sbcb

Sorted, pulled the handbrake shoe off and manage to bend the retaining clip back down (slipped a nail behind the inner part of the clip and folded the clip down over it, then took nail out). Holds the shoe firm against the hub now and the knock is gone (touch wood) but hasn't shown any signs in 3 good drives now. Still amazed such a little amount of play could create this noise. Also attacked the handbrake pad as per GK's thread - by the way GK was removing the edges the curer of any squeaky brakes?
Cheers guys for the responses, really helps out.
Carl

Glad you got it sorted Carl.

GK

frd906 · 08-11-2009, 01:00 AM

i still have the knocking noise, took it to my mech other day he said that the top control arrm is making the knocking noise, i had camber caster kit put it and new bushes

before i had the work done there was no noise, soon as i drove it home it started

should it make the noise when its been replaced, as its giveing me the s@#t

any ideas would be good cheers matt