Porsche Enthusiasts Club Forum

It is currently Tue Jun 24, 2025 6:22 pm
Classic Line Insurance


All times are UTC




Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: one other thing! (wheel wobble under braking)
PostPosted: Tue Oct 21, 2008 8:15 am 
Offline

Joined: Mon Jul 14, 2008 8:34 pm
Posts: 156
Location: Manchester
TIPEC membership: 0
One other thing! :lol:

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.

_________________
'88 944 Turbo


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Tue Oct 21, 2008 8:36 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Nov 04, 2007 7:43 pm
Posts: 12835
Location: Chatham, Kent
TIPEC membership: 4190
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.

_________________
Jim

http://tipec.net/region_southeastlondon.php

2018 Mitsubishi Outlander PHEV
2005 Porsche Cayenne S SOLD
2000 Jeep Grand Cherokee SOLD
2010 Mazda MX5 Mk3.5 2.0 Sport Tech SOLD
2000 Porsche Boxster S SOLD
1987 Porsche 944
2019 Abarth 595C


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Tue Oct 21, 2008 8:54 am 
Offline

Joined: Tue Oct 14, 2008 12:58 am
Posts: 161
Location: Wellington's Playground
TIPEC membership: 0
If the discs used were Zimmermann they will be warped.

_________________
Fen

2003 Jeep Wrangler with the top off all the time
1996 Jeep Cherokee with "bush stripes"

Oh, and the "Land Glider" 1990 944T that doesn't go and lives 12,000 miles away


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Tue Oct 21, 2008 9:05 am 
Offline

Joined: Mon Jul 14, 2008 8:34 pm
Posts: 156
Location: Manchester
TIPEC membership: 0
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?

_________________
'88 944 Turbo


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Tue Oct 21, 2008 9:27 am 
Offline

Joined: Tue Oct 14, 2008 12:58 am
Posts: 161
Location: Wellington's Playground
TIPEC membership: 0
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.

_________________
Fen

2003 Jeep Wrangler with the top off all the time
1996 Jeep Cherokee with "bush stripes"

Oh, and the "Land Glider" 1990 944T that doesn't go and lives 12,000 miles away


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Tue Oct 21, 2008 10:33 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Nov 04, 2007 7:43 pm
Posts: 12835
Location: Chatham, Kent
TIPEC membership: 4190
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 :mrgreen: , & yup the disc bells rust....
Mine came from Berlyn & I gather he only does Sebro now.

_________________
Jim

http://tipec.net/region_southeastlondon.php

2018 Mitsubishi Outlander PHEV
2005 Porsche Cayenne S SOLD
2000 Jeep Grand Cherokee SOLD
2010 Mazda MX5 Mk3.5 2.0 Sport Tech SOLD
2000 Porsche Boxster S SOLD
1987 Porsche 944
2019 Abarth 595C


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Tue Oct 21, 2008 6:08 pm 
Offline

Joined: Mon Nov 05, 2007 6:24 pm
Posts: 3008
Location: Halifax
TIPEC membership: 4636
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.)

_________________
944 lux, Eco car. Off the road more than it's on!
Audi 2.0 TDI Good but rather boring..........
944 now sold.


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Tue Oct 21, 2008 7:14 pm 
Offline

Joined: Tue Oct 14, 2008 12:58 am
Posts: 161
Location: Wellington's Playground
TIPEC membership: 0
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.

_________________
Fen

2003 Jeep Wrangler with the top off all the time
1996 Jeep Cherokee with "bush stripes"

Oh, and the "Land Glider" 1990 944T that doesn't go and lives 12,000 miles away


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Wed Oct 29, 2008 4:37 pm 
Offline

Joined: Tue Mar 25, 2008 7:05 pm
Posts: 211
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.


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Wed Oct 29, 2008 5:11 pm 
Offline
Moderator
Moderator
User avatar

Joined: Sun Nov 04, 2007 7:43 pm
Posts: 12835
Location: Chatham, Kent
TIPEC membership: 4190
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!

_________________
Jim

http://tipec.net/region_southeastlondon.php

2018 Mitsubishi Outlander PHEV
2005 Porsche Cayenne S SOLD
2000 Jeep Grand Cherokee SOLD
2010 Mazda MX5 Mk3.5 2.0 Sport Tech SOLD
2000 Porsche Boxster S SOLD
1987 Porsche 944
2019 Abarth 595C


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Wed Oct 29, 2008 11:13 pm 
Offline

Joined: Tue Mar 25, 2008 7:05 pm
Posts: 211
Jim,

Interesting, are there better ones you could recommend?


Oli.


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Thu Oct 30, 2008 8:21 am 
Offline

Joined: Mon Nov 05, 2007 9:36 pm
Posts: 547
Location: Kent
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 :roll:


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Thu Oct 30, 2008 8:39 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Nov 04, 2007 7:43 pm
Posts: 12835
Location: Chatham, Kent
TIPEC membership: 4190
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 :roll:


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 :evil:
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......)

_________________
Jim

http://tipec.net/region_southeastlondon.php

2018 Mitsubishi Outlander PHEV
2005 Porsche Cayenne S SOLD
2000 Jeep Grand Cherokee SOLD
2010 Mazda MX5 Mk3.5 2.0 Sport Tech SOLD
2000 Porsche Boxster S SOLD
1987 Porsche 944
2019 Abarth 595C


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Thu Oct 30, 2008 6:34 pm 
Offline

Joined: Mon Nov 05, 2007 6:24 pm
Posts: 3008
Location: Halifax
TIPEC membership: 4636
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!

_________________
944 lux, Eco car. Off the road more than it's on!
Audi 2.0 TDI Good but rather boring..........
944 now sold.


Top
 Profile  
Reply with quote  
 Post subject: Re: one other thing! (wheel wobble under braking)
PostPosted: Thu Oct 30, 2008 9:10 pm 
Offline

Joined: Mon Jun 23, 2008 1:27 pm
Posts: 934
Location: Oxford
TIPEC membership: 5218
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.

_________________
1983 Porsche 944 - Ongoing project/problem child
1988 Porsche 944S - Sold!
2002 Boxster 2.7 - Daily Driver


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next

All times are UTC


Who is online

Users browsing this forum: No registered users and 22 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group