Some timely help needed - knocking from rear of car.

[944Fripp]

Hi folk's!

I took my S2 to an indy to get an MOT, new rear disks and pads done as well as some geometry correction and a general look over everything. Was all sorted without any problems but then as I was driving home I started to hear a knocking noise from the rear of the car that wasn't there before I took the car in. The knocking comes in 2 forms - at low speed it increases in frequency as the car speed increases (directly related to wheel speed), it is difficult to hear at higher speeds but also at lower speeds I can hear a rattling/knocking when I go over bumps.

I asked them about it and they suggested the brakes may need some running in. I've done about 100 miles and it still rattles so it's going back on Thursday morning.

I can't get under the car to check but the wheel is solid (all bolts are tight) and the calipers also feel solid. The exhaust is solid (it is Dansk SS unit which isn't that old) and there's nothing loose in the boot that could create knocking. More importantly, the noise goes away when I put my foot on the brake and I think it is coming from the nearside rear (definitely the rear of the car). This leads me to think that it is the pads rattling in the caliper somehow and the anti rattle shims have been left off or fallen off.

Now, I am getting married this Saturday and the intention is to use the car to drive my newly wedded wife from our ceremony to our reception. Meaning that the car really needs to be fixed (or deemed safe!) for Friday. So, if nothing is obviously wrong with the car and it's not the pads rattling in the caliper what else could it be? I'd like to give my indy the best chance of fixing it in time so if there's anything 944 S2 specific that it could be then please let me know, it would be really appreciated!

Many thanks all as ever for your sage advice.

T

 

[pauljmcnulty]

Congratulations, Tom! We will need pictures of course. []

Can't help with the brakes, but I love a romantic story!

 

[andy watson]

Hi Tom,

Congratulations for Saturday, I would suspect CV joints if you can get under the car (no need to jack up) can you twist the drive shaft for and aft and see if there is too much play and you may feel it knock too?

Hope the S2 gets you there-----on time!!

 

[WXW611]

Were the handbrake pads changed? Could be a loose retainer spring. Or pads have been ground to compensate for pad lift (seen that).

 

[Monkeythree]

Take it back to the garage that did the work and tell them you're not happy with it.

 

[944Fripp]

ORIGINAL: pauljmcnulty

Congratulations, Tom! We will need pictures of course. []

Can't help with the brakes, but I love a romantic story!

Thanks Paul, of course...with ribbons and everything! If it is there with us of course...we'll both be very upset if not!

ORIGINAL: andy watson

Congratulations for Saturday, I would suspect CV joints if you can get under the car (no need to jack up) can you twist the drive shaft for and aft and see if there is too much play and you may feel it knock too?

Hope the S2 gets you there-----on time!!

Thanks Andy, I'll check them tonight. Seems like quite coincidence that they would go when the rear brakes are changed and odd that the rattle would go away when I brake but am still moving. Still, it wouldn't be the first time there was a strange coincidence! In fact, it would probably be stranger if it wasn't an odd coincidence.

I hope it gets there too. Although my car is being driven there by my best man, I'm being driven there by my dad in his 1931 Morgan Super Sports! []

ORIGINAL: WXW611

Were the handbrake pads changed? Could be a loose retainer spring. Or pads have been ground to compensate for pad lift (seen that).

They were changed at the same time. I'll ask them to double check this, thanks!

 

[944Fripp]

OK, I've had a good look under there and it all looks good. However, there's deffinately play and a clunk from the top of the nearside driveshaft. I think this could be the problem! If it is, is it safe to drive (I'll need to do about 50 miles max in it this weekend). The reason for asking is that if I call my indy tomorrow and ask them to order a driveshaft for it so that it's done in time and then it turns out to be a brake shoe or something daft and the play I felt was normal I don't want to waste the money! Should there be any play there at all?! The car was in gear when I was under there if that makes any difference!

Thanks for the help in narrowing the problem down!

 

[white944]

I reckon it's an insecure parking brake shoe.

 

[944Scott]

White 944 might be onto something there. Drive shafts have lateral play that will knock if you push/pull them hard enough.

I had something similar with another car which turned out to be one of the calliper bolts had come loose and was missing allowing the calliper to move around but the sound went away when braking.

 

[pauljmcnulty]

My first thought was the handbrake shoes, but I'm loathe to suggest things as I'm not at all experienced with the oily bits.

Mine were a nightmare after being re-fitted, with them being replaced three times before they stayed on. []

I drove from Wales to Rickmansworth with them rattling around, having driven from Brands Hatch to Rickmansworth the previous weekend with them rattling around.

Loads of tin cans on the back to disguise the noise, and the AA on speed-dial. If she's worth marrying she'll understand. [][]

 

[944Fripp]

ORIGINAL: pauljmcnulty

My first thought was the handbrake shoes, but I'm loathe to suggest things as I'm not at all experienced with the oily bits.

Mine were a nightmare after being re-fitted, with them being replaced three times before they stayed on. []

I drove from Wales to Rickmansworth with them rattling around, having driven from Brands Hatch to Rickmansworth the previous weekend with them rattling around.

Loads of tin cans on the back to disguise the noise, and the AA on speed-dial. If she's worth marrying she'll understand. [][]

Thanks Paul...you big softie! []

 

[944Fripp]

ORIGINAL: white944

I reckon it's an insecure parking brake shoe.

I think (and hope) you're right! There may be some play but I can't believe there's enough that when the driveshafts are under load from the gearbox it sounds like something is actually loose!

We'll see!

Thanks White944 and 944Scott!

 

[zcacogp]

I'm not that familiar with the handbrake shoe arrangement but would a loose one stop rattling when the brakes are applied?

All the best with the wedding Tom. We certainly need pictures of that!


Oli.

 

[944Fripp]

ORIGINAL: zcacogp

I'm not that familiar with the handbrake shoe arrangement but would a loose one stop rattling when the brakes are applied?

All the best with the wedding Tom. We certainly need pictures of that!


Oli.

I was thinking that this morning having driven it to work today so it can be valeted (there's always hope for the day!). The rattling definitely stops when I put my foot on the brake, I don't even need to brake hard to stop the rattling which would suggest its not the CV joint, the drive shaft or the handbrake shoes but more related to the caliper or the pads.

Thanks for the well wishes Oli, saying such nice things you must surely be in danger of having one of your ban's lifted. []

 

[zcacogp]

That's my thinking as well - if it stops when the brakes are applied then it's related to something that is loose when the brakes are off but which tightens up when they are applied. I'd be suspecting the pads, for sure.

If you get a chance before the big day then I'd be jacking the car up and taking the wheels off and looking closely at the pads. Are they at all loose when the brakes are off? The cruciform spring that forms a gate to hold them in can sometimes sit in such a position that it doesn't hold them tightly in place, so it may be worth taking them out and putting them back in and making sure that the spring is properly in contact with the edge of the pad. However, if it is the pads rattling then it will be nothing more than annoying; it won't have any effect upon the brakes themselves and won't make the car unsafe to drive.

The only other possibility is that it could be the brake shield becoming detached from the hub. However this gives a very different sort of rattle (much lighter and tinnier) and wouldn't stop when the brakes are applied, so it probably isn't this.

ORIGINAL: 944Fripp
Thanks for the well wishes Oli, saying such nice things you must surely be in danger of having one of your ban's lifted. []

No, that's not the idea at all - silly boy! I'm aiming for the quadruple-ban, not trying to reduce the count. (But I'm not about to be rude about your nuptials to achieve this - I hope it's a great day! [] )


Oli.

 

[944Fripp]

ORIGINAL: zcacogp

I'm not about to be rude about your nuptials to achieve this - I hope it's a great day! [] )

How very decent of you Oli, I'll be sure to put in a good word for you with Paul. Haha! []

 

[zcacogp]

Bu99er - I give up! []

 

[944Fripp]

Hi all,

For those that offered some advice...and for those that are just plane soppy, here is a nice picture of my 944 at my wedding...yep, if you were following this thread, it made it! My wife and I have spent many happy hours before in the car and it was lovely to have it with us on the day.

Despite the fact that it chucked it down with rain, it was a fab day and the car gave us no problems on the way to or from the ceremony...apart from tearing through the ribbons mounted in front of the windscreen...they were torn off by the windscreen wipers shortly before arriving! []

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The car pictured next to it is my dad's 1931 Morgan 3 Wheeler Super Sports which he took me to the ceremony in (he's had it since he was 18 and rebuilt it himself about 15 years ago). It's a pig to drive (no syncromesh, hand throttle, hand start and manual advance/retard etc) but the experience is immense! Almost as good as the fly by my best man gave us in the 944 at full chat on the way into Sheffield! You forget how good that 3.0L engine sounds at 6,000 RPM when it's only you that normally drives it! []

 

[944Turbo]

Congratulations!

 

[zcacogp]

Fab! Did you get to the bottom of the rattle?

Working on the car should be easier now that you have a live-in assistant to help hold the spanners. That's when she's not washing up / ironing / hoovering / dusting, of course! []


Oli.