Intermittent wheel shudder - CV?

subalex · Post by **subalex** » Thu Jan 10, 2008 7:12 pm

I've got an inconsistent steering shudder that is quite noticeable. I've replaced everything from CV's and lower control arm to bearings and wheels in the past months and it's continued. I've taken it to the mechanic for a wheel alignment and they had a thorough look over. The near side (passenger side) front wheel shudders a little on take off and I pointed out that the inner cup of the CV I changed on that side is a new one I bought but doesn't seem to fit snuggly compared to the genuine Subie one on the off side. So, has anyone else found the same? I've already has the company I bought it from send me two more CV's for the exact same problem (inner cup being too loose on the output shaft of the gearbox). This seems to be the explanation for the shuddering right fellas?

Shudder comes along when backing off throttle and also on acceleration from standing start.

AndrewT · Post by **AndrewT** » Thu Jan 10, 2008 10:18 pm

Is the inner cup VERY loose on the gearbox stub or just slightly?
If its very loose then you have the wrong one, there are two types - 23 spline and 25 spline, 25 spline being bigger.

Otherwise maybe it's...
- clutch problem, maybe the pressure plate has a busted spring, I've heard of this causing shudders like that
- steering rack wear - although this would probably have been detected when having the wheel allignment done
- engine or gearbox mount broken

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Thu Jan 10, 2008 11:22 pm

Another one i have had that did the same was rear tyres being worn out.

stamp_licker · Post by **stamp_licker** » Fri Jan 11, 2008 9:02 pm

The splines on the hub may be worn.Also if you,ve got nankangs run your hand around the sidewalls if you can feel ripples they're shot.

subalex · Post by **subalex** » Sun Jan 13, 2008 3:09 pm

Thanks all for your suggestions. I've checked off all of them considering the evidence and there's still no solution yet.

I just changed the steering rack for another power steer one just last week(needed doing anyway).
I counted the splines of the first and second pair of CV's I got from the supplier and they're all 23 spline (as they should be).
I felt the Nankangs (only about 2000 k's old) and, nope, they're not shot. I also rotated them all.
I tightened the crown nuts on the CVs.
I fitted new front wheel bearings and seals about 10,000k ago.
I've tightened the wheel plate on the hub.
Tightened the wheels on the hubs.
Yesterday I completely flushed the brake system (definitely needed doing) and tightened up one of the brake lines in the engine bay that doesn't keep still in its plastic guide/clamp.
I checked and tightened up the front brake lines where they attach to the shock body.
The output shaft of the gearbox wasn't loose with a genuine (but worn out) CV put on it as a trial.

I driven it again today (to Wheeny Creek - a great spot only 1/2 hour away) and it was better after the attention to brakes. However it's still inconsistent. I figure it's a combination of a) the brakes needing machining (thanks to problem 'b') and b) the CV is not quite the right diameter in the hub either (just like the slight oversizing of the inner cup) so it's moving out of centre all the time.

I'm certainly calling the company again to rectify their "Completely new CV shafts" that they've sent to me twice now. Obviously the price (cheap) spells inaccurate. I should be able to get my money back and try something else better. Once that's done I'll machine the front discs too and see how it goes.

fredsub · Post by **fredsub** » Sun Jan 13, 2008 3:15 pm

I recall once I had very pronounced shudder when braking down hill in a curve - got the brake disc s machined

is your shudder more evidenced under braking ?

Matatak · Post by **Matatak** » Sun Jan 13, 2008 10:36 pm

Radius Rod bushes. or any other bushes?

subalex · Post by **subalex** » Mon Jan 14, 2008 9:50 pm

Thanks again for the suggestions... yes, I did tighten the radius rod bushes, even changed the whole lower control arm and radious rod in one piece for a spare I had just two weeks ago. I've checked on it since too and I'm buggered if I can get it any tighter. Regarding the shudder under braking... yes, usually it is worse. But that's the thing...USUALLY and not always.

I'm definitely getting the discs machined now. They seem to be the next thing in line for checking and since they are obviously contributing to the problem I'm going to cancel that part out. From there it could be...
- a loose brake pad
- a dodgy bolt supporting the radius rod end bracket to the body
- a dodgy, out of spec, cheap CV
- dodgy bearings

I hate holidays... it's always during them that I get around to a decent drive and I notice things that need doing and I'm too picky... a stitch in time I say.

Matatak · Post by **Matatak** » Tue Jan 15, 2008 12:18 am

take front shafts out and run RWD for awhile. see wt happens.

and i meant are allt he bushes good. they culd still be screwed in ur spare control; arm.
and tightening em wont fix a screwed bush.

subalex · Post by **subalex** » Tue Jan 15, 2008 4:16 pm

Can't take the front shafts out... the hubs are all bolted together on the basis of the CV shaft holding them all together. As for the bushes... yeah... I checked them all out for the two best ones to choose from and I only had those replaced a couple of years back anyway. I appreciate those ideas trickling in. Today I checked the lock nut of the front brake assemblies and they were both as tight as I dared a few weeks ago when I checked for this back then. I checked the Gregory manual and it said only to have them at 47Nm or something like that so I loosened them off and tightened them much more gently than before. I've got to get a torque wrench for jobs like this. It's about time... I've got pretty much every other tool. Still, I don't know what impact this will make. I'm getting the brakes machined tomorrow if all goes well so will keep all informed.

Took the car for a drive this afternoon to pick the boys up from kindy and it's a very different matter having only adjusted the lock nut as mentioned above. Still needs machining of the discs though. Looking good so far.

Matatak · Post by **Matatak** » Tue Jan 15, 2008 7:03 pm

dont know wt lock nut ur talking bout...

yer u wuld need an outer CV joint to stickback in when u take the shafts out to make it drivable.

did u rotate wheels?

fredsub · Post by **fredsub** » Tue Jan 15, 2008 9:55 pm

hey on the machining of disc s, I was not 100% satisfied until much later replaced them with new......
anyway i'm sure the brake place you go to will advise either way, If it indeed is them causing shudder problem, and your not even braking,then probably really bad gone,

subalex · Post by **subalex** » Tue Jan 15, 2008 10:47 pm

Hmm.. I don't have any spare CV outer joints on their own. Full shafts... but I'm not keen on separating them.. don't know how. Yes, I did rotate the tyres too. S**t, what haven't I done?? LOL

I'm actually a little tempted to swap over the discs and calipers from the old hubs that I still have from when I did a bearing change. I had them machined only a few thousand k's earlier. Still... I'd rather get this done for $45 I was quoted for it being done on-car instead of spending more time on it myself. My time is far more costly than that since I've got a holiday to try to enjoy and there's work I intended to do weeks ago during this break but the car's taken time away from that. LOL... bitch bitch bitch...

Ah well, the wife's coming home from Melbourne after a 4 day holiday so I'm getting the brakes machined before heading off to the airport tomorrow. Good thing she's got the eldest with her... there just ain't enough seats for 5 kids.. you should see how the 9 year old squeezes in between the two booster seats....ever seen a sausage burst when it's being BBQ'd???

Oh... how is she coming home in the L? She won't be... she drove to the airport in the family mover, she'll be driving back in the family mover.

SUBYDAZZ · Post by **SUBYDAZZ** » Wed Jan 16, 2008 3:26 pm

In my experience, my Subarus have had a lot of issues with discs warping / constantly needing machining (and no, they don't last long before you reach minimum thickness). I've come to accept light shuddering under braking as a standard factory option. It usually disappears under heavier brake application, if it doesn't something else may be wrong.

subalex · Post by **subalex** » Sat Jan 19, 2008 11:51 am

Ok guys, I had the discs machined - on car - which is the best option. THe fellow who did it measured how far out they were and he said that one side was out by 5 thou and would have given some shuddering effect. Perfectly even on both sides now, the brakes are infinitely better with regards to shuddering. None present through the pedal any more. However, the same bloomin' shuddering is still present on and off and I reckon it's through that stupid front CV so I'm going to take it off and replace it with a better brand. I've already arranged it with my local machanic.

While that's being done I'll get him to check the bearings... they've had a fair chance of getting mud and muck into them since I changed them 2 years ago but they have the rubber sidewalls to them so they should be alright.

rossandhazel16 · Post by **rossandhazel16** » Thu Jan 31, 2008 8:09 am

I have a Brumby that is very sensitive to Wheel Balancing. Have Sunraysia wheels fitted and get them balanced on the "Studs" instead of the centres as is usually done because it is quicker. Worked for me.

subalex · Post by **subalex** » Fri Feb 08, 2008 7:34 pm

Believe it or not I'm still waiting for this shop to sort out what they're doing about these CVs. The fellow finally agreed that they are indeed from a supplier who never seems to get the inner joints quite right. (Well duh!)

I've minimised driving the car in the last couple of months so as not to wear anything else out (let alone not drive me insane).

As for the 14" Speedy Desert Rats... yep, typically the centre hole isn't quite dead centre... I learnt that trick a few years ago too.. here on the forum too
what a good place this is huh

.

If I don't get some action from them soon then I'll be leaning on them a lot harder.

Post by **Alex** » Fri Feb 08, 2008 8:30 pm

one thing you havent done is the tailshaft. It could be slightly bent or out of balance. I had pretty much exactly the same problem, and the uni-joints in the tailshaft had shat themselves.

DEFINATELY get them checked out.

at least your getting all new bits while your trying to fix the problem.

PS. great name

alex

AndrewT · Post by **AndrewT** » Fri Feb 08, 2008 8:51 pm

I'll second that suggestion, tailshaft uni joints can definitely cause this symptom.
Take the tailshaft out (2 minute job) and waggle the uni joints from side to side, they should move smooth and easy.
If they are either difficult to move, or notchy when they do move then they are most likely the culprit.

Subaru tailshaft uni joints are the "non replaceable" type. This means they can be replaced but it's just abit more difficult. Any good driveshaft/tailshaft workshop can still do it for you.

**Edit - also, you could try running Front Wheel Drive only for a short time. Take the tailshaft out, cut an empty Coke can in half, put this over the back of your gearbox and secure with a large cable tie to stop the oil leaking out (This works very well!!).
Take it for a drive with no tailshaft and see if thats the problem.

YouTube · Post by **El_Freddo** » Sat Feb 09, 2008 10:08 pm

AndrewT wrote: **Edit - also, you could try running Front Wheel Drive only for a short time. Take the tailshaft out, cut an empty Coke can in half, put this over the back of your gearbox and secure with a large cable tie to stop the oil leaking out (This works very well!!).
Take it for a drive with no tailshaft and see if thats the problem.

With the L's two piece tail shaft you can take out the last half of the tail shaft and still safely drive with the first section in the car - that said, the first section's uni joint could be the culprit anyway...

Bennie

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Intermittent wheel shudder - CV?

Intermittent wheel shudder - CV?

Wheel shudder