Rattle when braking - engine

U

Un4tural

Member
Hi All,

I've been enjoying relatively worry free motoring and not really doing much more work on the car, waiting until i can take her apart give it a nice clean in and out and see about rebuilding the motor/gearbox checking bearings etc. without having to hurry, well i feel i wont have that.


Now when braking hard but not abnormally hard i have the idling noise (not sure what to call it) much more pronounces, in idle, though might just not hear it when in gear.

Cannot find any posts of this issue, but it seems like big end rod bearing?

It is TDI 90 ATL motor - now i suspect it might have other internal wear or damage due to few invoices stating no oil.

I'll try and record it but i doubt it'll come out well due to other noise etc. when braking... having windows open seems to hide the noise really well too but i rather not have sump fall off.

Had a look over mounts and everything seems fine other than heat shields around exhaust being loose, will tidy those up for the sake of "being hopeful" as giving engine a tug those do make a bit of noise and if it is just those resonating i will be super happy.



Now more realistically if i do need to do the bearing, is it accessible with just the sump off or does it need heaps of bits taking off? As if it is engine out job i probably would need to find somewhere to store her until i have somewhere to work on that...

Sorry bit of a long write up and if you have ideas on checks that might save her from deep freeze let me know :/ it does have bit of shake to clutch pedal as well, which could be related as well i guess - transferring vibrations from engine/shaft.
 
Special edition said:
Could all these "symptoms" simply be linked to a warn dual mass flywheel. ?
Click to expand...
Sorry forgot to mention - It is with a new clutch/dmf assembly from LUK, about 8k miles on it now.

The wobble remained in the pedal with fresh dmf too, but most posts online state it is "normal" according to vw/audi for tdi pedal to have a bit of wobble, but i feel it is just to hide some short comings.
 
You are running the correct grade of quality oil to the correct level on the correct dipstick? Do you only get the noise braking in gear , braking clutch in or braking already in neutral? How old is the gearbox oil? correct grade and quantity? Heat shield around turbo and driveshaft secure? Bonnet rattling in top mounts? Under tray loose? Something left on the under tray? Loose or warped discs? Sticky caliper? Loose wheel bolts? Lots of questions unfortunately may not even cover the reason for your noise.
 
Car is maintained fairly well, oil changed just after new year both gear box and engine, filters, brake fluid everything all round really. Oil levels good all liquids good.

I only notice it when it is in neutral with clutch pedal in but hard to say with road noise, it is not super pronounced, but noticeable and seems to get better once warmed up. Will definitely try and capture some audio next time I take her out.

Everything is secure, bonnet etc. The heat shield flange is removed due to being worn through and has been off since clutch/dmf replacement. Will get another at some point. I've tidied up the arch lining as that was rattling a little bit but do not see anything else wobbly other than mentioned heat shield around rear around exhaust. Car sadly did not come with under tray.

All wheels are torqued, discs and pads new (well less than 5k on them) guide bolts done all around as well.

Might give gearbox top mount a replacement but went over underside engine bay and nothing is loose or rattly, and gave engine a bit of a tug and shake with no noises either though it was off, not quite at a point in my life to shake it while it is running on stands :)

Overall I've tried to look after it well and it is mostly up to date maintenance and rattles wise, main concern is the motor as it seems to have had some neglect in the past and it is not something I can correct in depth currently...

Overall it pulls and goes well, other than bit of smoking when foot to the floor as turbo sometimes takes a while to wake up which is on my to do. Other than that she's been faultless(minus a crank sensor few months ago and oil level sensor few days after that).

No work was done for over a month until this rattle/knock. Bolts are torqued to spec in manual or handy dandy forum thread.

It really sounds like engine is tipping over in idle when braking, though with Window wound down I can't tell if the noise is there.
 
Try without the bonnet fitted. Vacuum connection to the rear of the tandem is not loose? Still could be a DMF / clutch issue, quality is not what it used to be, especially if they did not change ALL the clutch components.
 
I've fitted the whole assembly myself with a mechanic friend (surprising how everything makes sense fitting it back together).

It was not separate bits and came pre-assembled just had to bolt it to the engine then massage the gearbox back on. Mind I did see some posts about portion of luk clutches/dmfs being recalled so will be pretty annoyed if it is that... Again.

Absolutely everything was replaced in there as I did not want to have to go back in there. Fork, top hat, throw bearing, clips etc. All of it. Didn't want to take chances :)

Gearbox/Clutch issue looking for thoughts

Hi fellas, Another update - fresh gear box oil old stuff looked like a caramel/chocolate soup - probably good idea to do gearbox oil if it hasn't been changed as most aren't i am guessing. Will get a clutch kit plus other bits to go with it to get it to tip top shape @depronman could you...
www.a2oc.net

Didn't take pictures of the thing back in there sadly but we were pretty knackered after wrestling gearbox off it for good few hours as the clutch disc was climbing over the surrounding bracket not letting go, sorry going off topic here.
 
Greased the splines? Perhaps it is a faulty unit. When was the brake fluid last changed. Many forget the clutch slave is fed from the brake reservoir and do not bleed / flush the clutch slave. Quick and easy to do so not much to lose.
 
Did brake fluid few months ago as well as had a brake piston leaking, bit after doing brake all round.

Will give a try with clutch slave bleed though, just in case some air made its way there... That'd be a lucky break for the pedal shake but doubt will solve my rattle when stopping.

I am really really hoping clutch/dmf isn't faulty here :D that'd be such a pain
 
Right, rattle is now gone.

Could not say for sure what it was though as nothing drivetrain wise was loose or rattly. Looks like flexi pipe needs doing soon which will presumably be the whole exhaust doing.

Main thought is the tensioner for accessory belt as that seemed to be tensioning more in hops than smooth movement - bit of oil and it is nice and smooth again.

Tidied up front bumper plastics etc. but nothing i would suspect of a rattle like that.

Bit of glitter in the oil but nothing major or visible damage, can of engine flush and fresh oil+filter, does seem to sound soother but could just be me happy lying to myself.

Did not take pictures as was bit of a slip and slide sadly.

Will put some miles on and see how she does, hopefully that was it and nothing else to worry about, other than issues on my radar already.

Also drive shafts seem to be getting rusty with the paint peeling so will probably get those renewed soon as well, though no wobble that i can feel yet.
 
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