Help! my car doesn't work properly
Discussion
Help!!!!!!!!!!!!! I've had my '96 993 c2 for approx 8 months now, and had a bloody annoying judder from the rear of the car for most of that time. I am now nearing the end of my patience and want the problem sorted. The background: Bought the car from a Lexus garage, they replaced the rear discs but with non-OE parts. Drive for approx 1,000 miles then notice a juddering sound and feel coming from the rear of the car, this appears to get worse when the brakes are warmed up and is only really noticeable above, say 70 mph. Take the car back to the garage, they skim the discs and everything is OK for a few hundred miles. Then the problem comes back, I get angry and demand new discs, they oblige but again with the non-OE parts. I am less than happy and voice my concerns, but go along in the knowledge that they will provide OE discs if the same happens again. The same does happen approx 1200 miles later. I then - very frustrated - take the car to local Porsche Indie, who says the pads are low and look as though they are not set properly. He replaces pads all round (calliper plates are apparantly OK and not rusty) thinking that this could be source of problem. I pick the car up and he says he has tested it and its sorted. I drive it away dial up 85 mph, brake, and there is the juddering.
Now I'm sick and go back to Lexus demanding OE discs for the rear. They then oblige and provide two lovely grey painted OE discs. These are fitted and it seems to cure the problem. That was until Saturday when I noticed the problem coming back again. Now it is just as bad as before.
A couple of points: I have always felt that the car suffered a slight 'wobbling' at higher speeds from the rear. On smooth roads it feels almost like the rear wheels are out of balance and when the brakes are applied, it simply accentuates the wobbling to create the judder through the pedal and my arse. Most people don't seem to notice the 'wobbling' when I tell them but I know it is there. In the course of the various investigations, the wheels have been off and balanced, then stripped down and re-lacquered. I have also recently replaced the rear tyres, so its not some form of tyre abnormality.
I am struggling to believe that the discs are the problem. The last 1200 miles I have done I have not been hard on the brakes, in fact a lot of the miles have been motorway and I've been bedding them in. The most confusing thing however is that when the discs have been replaced, the problem is cured for a while. If it wasn't the discs then surely the problem would be there even when the new discs were put on. Unless of course something is working loose that is subsequently tightened up when the discs are replaced. In which case, should I get someone to take the discs off, then put them back on again to see if that makes a difference??? The problem is that I am really grasping at straws because I don't know enough about it. My fatha is wondering whether it could be play in the bearings, or imperfection in the hub (but then why would it be OK for 1200 miles??), but again, we don't know, and neither does my mechanic mate who has two 911s and works on them a fair bit. The indie I took it to doesn't know, Lexus don't know - nobody seems to know!!
As you may have guessed, this post is borne out of sheer desperation and I appeal to all you people out there who know these cars like the back of your hands, to share some thoughts as to what it could be. I hope I have explained it enough but please tell me if it isn't clear. Many thanks in anticipation.
Adam
Now I'm sick and go back to Lexus demanding OE discs for the rear. They then oblige and provide two lovely grey painted OE discs. These are fitted and it seems to cure the problem. That was until Saturday when I noticed the problem coming back again. Now it is just as bad as before.
A couple of points: I have always felt that the car suffered a slight 'wobbling' at higher speeds from the rear. On smooth roads it feels almost like the rear wheels are out of balance and when the brakes are applied, it simply accentuates the wobbling to create the judder through the pedal and my arse. Most people don't seem to notice the 'wobbling' when I tell them but I know it is there. In the course of the various investigations, the wheels have been off and balanced, then stripped down and re-lacquered. I have also recently replaced the rear tyres, so its not some form of tyre abnormality.
I am struggling to believe that the discs are the problem. The last 1200 miles I have done I have not been hard on the brakes, in fact a lot of the miles have been motorway and I've been bedding them in. The most confusing thing however is that when the discs have been replaced, the problem is cured for a while. If it wasn't the discs then surely the problem would be there even when the new discs were put on. Unless of course something is working loose that is subsequently tightened up when the discs are replaced. In which case, should I get someone to take the discs off, then put them back on again to see if that makes a difference??? The problem is that I am really grasping at straws because I don't know enough about it. My fatha is wondering whether it could be play in the bearings, or imperfection in the hub (but then why would it be OK for 1200 miles??), but again, we don't know, and neither does my mechanic mate who has two 911s and works on them a fair bit. The indie I took it to doesn't know, Lexus don't know - nobody seems to know!!
As you may have guessed, this post is borne out of sheer desperation and I appeal to all you people out there who know these cars like the back of your hands, to share some thoughts as to what it could be. I hope I have explained it enough but please tell me if it isn't clear. Many thanks in anticipation.
Adam
Never forget that the 993 is notoriously sensitive to rear suspension geometry - all that passive steering and so on means that the 5 link set up has to be set up "just so".
Painful as it is, a £150 geometry check up could be the cure. Even if it isn't, most specialists advise getting the suspension geometry checked once in a while anyway - when was yours last done?
Is the wobble being generated from one side or both? any way to tell? Jack rear of car up, secure front wheels, start the engine and stick it in second... with both rear wheels spinning (off the ground) can you see anything odd?
Check suspension bushes very carefully also...
Just what i would do in your shoes.
VS
Painful as it is, a £150 geometry check up could be the cure. Even if it isn't, most specialists advise getting the suspension geometry checked once in a while anyway - when was yours last done?
Is the wobble being generated from one side or both? any way to tell? Jack rear of car up, secure front wheels, start the engine and stick it in second... with both rear wheels spinning (off the ground) can you see anything odd?
Check suspension bushes very carefully also...
Just what i would do in your shoes.
VS
domster said:
What about the wheel bearings?
Sound slike something is loose with the rear hub. I had strange vibration under braking on a trackday once - rear wheel was coming off! if wheel nuts are OK, get them to check hub assembly and especially wheel bearing.
Just a thought.
Thanks for that - did wonder about the hub myself, it just seems confusing that when new discs are put on it clears the problem for a few weeks. Very frustrating - will get them to look at hub next time. Cheers.
verysideways said:
Never forget that the 993 is notoriously sensitive to rear suspension geometry - all that passive steering and so on means that the 5 link set up has to be set up "just so".
Painful as it is, a £150 geometry check up could be the cure. Even if it isn't, most specialists advise getting the suspension geometry checked once in a while anyway - when was yours last done?
Is the wobble being generated from one side or both? any way to tell? Jack rear of car up, secure front wheels, start the engine and stick it in second... with both rear wheels spinning (off the ground) can you see anything odd?
Check suspension bushes very carefully also...
Just what i would do in your shoes.
VS
I have just had the rear geometry done last week due to a general skittish feeling of the car (now suspecting rear dampers which will replaced very soon), and it was a few days - and a few hundred miles - after this that the vibrations returned.
Don't know which side it is coming from - might be a good idea to raise it up - cheers. I will get the suspension bushes checked when I replace the dampers.
Sounds like a bugger to diagnose. Unfortunately, this being the case, it could cost £££££ at £40/hr to pay a good specialist to get to the cause. Beware the muppets that just change things on a hunch. They will charge you for the parts & the labour & if it still ain't fixed, well thats just tough!
You need to build a relationship with a talented mechanic who uses his brain - it may not necessarily be a Porsche specialist BTW. In my experience, the expereince is great for saving hours on jobs that they do all t he time. But, for diagnosing an odd fault - you need logic, experience and clear thinking. You could do worse than post a query on th ernnlist 993 forum. Many, many experience 993 owners on there.
Good luck
You need to build a relationship with a talented mechanic who uses his brain - it may not necessarily be a Porsche specialist BTW. In my experience, the expereince is great for saving hours on jobs that they do all t he time. But, for diagnosing an odd fault - you need logic, experience and clear thinking. You could do worse than post a query on th ernnlist 993 forum. Many, many experience 993 owners on there.
Good luck
funny that you are getting the shocks done, a friend with a 944 had a brake judder that he never got to the bottom of, when he changed his shocks (MOT fail) the judder vanished forever.
My best guess was that the car was bouncing on the springs under braking with no damping effect from the shockers, and since the geometry changes slightly when compressing the suspension this produced the wobble...
Oooh, you've got me all interested now. Do keep us up to date on what happens won't you?
VS
My best guess was that the car was bouncing on the springs under braking with no damping effect from the shockers, and since the geometry changes slightly when compressing the suspension this produced the wobble...
Oooh, you've got me all interested now. Do keep us up to date on what happens won't you?
VS
Thanks John - most of the work that has been undertaken to date, has been done at cost to Lexus (I have a 12 month warranty) as the problem has been there since I got the car.
Cheers for the rennlist suggestion, I have just posted and look forward to any response. See what you mean about a good mechanic, and if anyone knows of one in the north east, please let me know.
Will keep on trying - its such a great car in every other way and when they are working, the brakes are immense.
Cheers for the rennlist suggestion, I have just posted and look forward to any response. See what you mean about a good mechanic, and if anyone knows of one in the north east, please let me know.
Will keep on trying - its such a great car in every other way and when they are working, the brakes are immense.
I had similar from the front of my 996TT and once I had all 4 drop links replaced the issue was cured. It is a 996 weekspot so not sure of relevance for 993.
Infact generally speaking bushes can wear out / perrish much faster than many thing and I am sure a 993 is sensitive enough for this to manifest obviousely.
Infact generally speaking bushes can wear out / perrish much faster than many thing and I am sure a 993 is sensitive enough for this to manifest obviousely.
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