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| one other thing! (wheel wobble under braking) https://forums.tipec.net/viewtopic.php?f=25&t=1996 |
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| Author: | Scho [ Tue Oct 21, 2008 8:15 am ] |
| Post subject: | one other thing! (wheel wobble under braking) |
One other thing!  When in brake at speed i get a slight wobble through the steering wheel. it seems to get worse the more i harder i work the brakes. The pads have plenty left in them, i have documentation of a full brake overhaul in '06 (£2500 spent). new front calipers, new discs, hoses, and pads all round. i think the cars done around 8-10k since. Any ideas on the cause of this wobble? Thanks in advance, Rick. |
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| Author: | tr7v8 [ Tue Oct 21, 2008 8:36 am ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
If it gets worse when the brakes are hot I suspect it could be disc run-out which the 944 is very sensitive to. The discs need checking with a dial gauge to see what is going on. It could also be hot spotting where the car os driven hard, the brakes get hot & then the car is bought to a stop with the brake pedal down, this causes either local distortion of the disc or transfers pad material to them which then causes judder. It can be cured by skimming if someoen does it locally. It's also worth doing a suspension check because wear in the front suspension bushes can cause this, especially the front bush on the wishbone. |
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| Author: | Fen [ Tue Oct 21, 2008 8:54 am ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
If the discs used were Zimmermann they will be warped. |
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| Author: | Scho [ Tue Oct 21, 2008 9:05 am ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
tr7v8 wrote: It's also worth doing a suspension check because wear in the front suspension bushes can cause this, especially the front bush on the wishbone. I've been thinking about replacing my bushes anyway to be honest. I can't find any record of the suspension having any work at all in 108K. Is it a job you can do yourself? I'm not so hot with the spanners but I have a good friend thats very good mechanically that could help me with it. Where's a good place to get replacements and which one's would you advise on swapping? Fen wrote: If the discs used were Zimmermann they will be warped. no details regarding what brand they were, just a price of £210 for the pair. if i end up replacing what would you recommend? |
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| Author: | Fen [ Tue Oct 21, 2008 9:27 am ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Anything else - in practice Brembo or Serbo. Have the bells rusted? Zimmermann are too cheap 'n' nasty to paint them. Every set of Zimm discs I have had have warped, not just on the 944 either. |
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| Author: | tr7v8 [ Tue Oct 21, 2008 10:33 am ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Fen wrote: Anything else - in practice Brembo or Serbo. Have the bells rusted? Zimmermann are too cheap 'n' nasty to paint them. Every set of Zimm discs I have had have warped, not just on the 944 either. Mine are Zimmerman, never had a problem, must be the way you fit emm... Fen  , & yup the disc bells rust....Mine came from Berlyn & I gather he only does Sebro now. |
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| Author: | J.J. [ Tue Oct 21, 2008 6:08 pm ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Got mine from GSF. Painted the bells body colour. If you work the brakes hard don't sit with the your foot on the brake after you've stopped. The extra heat from the pads can warp the discs. Get you foot off & use the hand brake. Mine are still fine too!  (Only done 15K on them though.)
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| Author: | Fen [ Tue Oct 21, 2008 7:14 pm ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Interesting Bert does Sebro now though, eh? I remember disagreeing with him on Titanic about Zimms warping, but I wonder if he got sick of processing warranty on them? Mine warped on my S2 cab which was a motorway car and my 530d (twice) which was also a motorway car - no heavy usage at all, and the Brembo replacements were fine in both cases with identical usage. Plus you need to paint them so they don't look nasty from 3 days after fitting them. Not worth the hassle and risk IMO. |
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| Author: | zcacogp [ Wed Oct 29, 2008 4:37 pm ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Bert also does ATE, which is what he sent me when I changed the disks on mine ... I had similar symptoms as described by the OP. Turned out that the wheels were slightly out of balance, but the wobble was too slight for me to notice when driving normally (if I concentrated I could just about detect it, but didn't notice until investigating the problem.) When the brakes were put on, the extra clamping on the disks was enough to transmit the vibration to the steering. (Interestingly, the wheel bearings are not shot - which was my first concern.) The lack of balance was due to the placing of the locking wheel nut in relation to the tyre valve. Moving it has solved the problem. Oli. |
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| Author: | tr7v8 [ Wed Oct 29, 2008 5:11 pm ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
zcacogp wrote: The lack of balance was due to the placing of the locking wheel nut in relation to the tyre valve. Moving it has solved the problem. Oli. The cheapy locking wheelnuts are a pain for this, as they are made from steel. They also have a habit of seizing on & giving grief to get off. AMHIK! |
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| Author: | zcacogp [ Wed Oct 29, 2008 11:13 pm ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Jim, Interesting, are there better ones you could recommend? Oli. |
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| Author: | Li Moo Bai [ Thu Oct 30, 2008 8:21 am ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
I recently got a set from our local OPC and they seem to have made a noticable difference to the feel of the car, with less vibration due to wheel imbalance. I think that since they are the same size as the rest of the nuts and same material (ally?) then the placement relative to the valve becomes insignificant. Adam p.s. when i bought my car it had the cheap steel ones which rounded off after several uses 
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| Author: | tr7v8 [ Thu Oct 30, 2008 8:39 am ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Li Moo Bai wrote: I recently got a set from our local OPC and they seem to have made a noticable difference to the feel of the car, with less vibration due to wheel imbalance. I think that since they are the same size as the rest of the nuts and same material (ally?) then the placement relative to the valve becomes insignificant. Adam p.s. when i bought my car it had the cheap steel ones which rounded off after several uses Yup I'd use the OPC ones as well, not sure if they are available from other sources such as Jasmine. Yup I had the cheapy ones round off as well, needless to say I had a slow puncture & I was in Yorshire at the time  Even the tyre dealers couldn't get it off! I removed it in the end with an old socket & a BFH! Scrapped both socket & wheelnut but who cares. I don't run any now, 16" D90's aren't the most desriable wheel! (Gets back from Finland to find Pork on Bricks......) |
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| Author: | J.J. [ Thu Oct 30, 2008 6:34 pm ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Just got a set of new alloy nuts for mine. Stuff the locking ones. Can't see anyone being bothered to pinch my wheels. Easier to steal the car! |
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| Author: | madrob6 [ Thu Oct 30, 2008 9:10 pm ] |
| Post subject: | Re: one other thing! (wheel wobble under braking) |
Where did you get them from and how much were they if you don't mind me asking? I need a new set for mine as the rears are falling apart. |
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