Slow speed turning shudder.

euph0r1a · Postby **euph0r1a** » Tue Sep 10, 2013 6:32 pm

Hi all,

My '90 Roadster has a quirk where, at slow (i.e. carparks, stop signs) speeds, turning, especially right, causes the whole car to shudder/vibrate for the duration of the turn, and then return to it's normal state. It doesn't seem happen when turning a corner at speed, and never in a straight line.

Car starts up first time, every time, but occasionally does emit a high pitched squeal for a few seconds coming from towards the front of the bonnet, which then disappears and doesn't happen again. The squeal probably happens 5-10% of the time when it's turned on, usually when the wheel is already turned.

I'm pretty inexperienced when it comes to diagnosis, so any advice would be appreciated. I took it to my usual mechanic who had worked on a few 5's previously, and had no clue what was causing it.

I'm waiting for a low profile jack to be delivered to get under the car and change the diff/gearbox oils, as well as engine oil. I've just bought the car last week, and it seems to have spent most of it's time not being dríven, so it could be the VLSD needing an oil change.

Possibly the power steering? Because it only happens when the power steering would be in use, and from a bit of reading the power steering belt could possibly be loose.

Suspension seems to be original (so 20+ years old), KYB Buzz Spec adjustable shocks, could be worn/scrubbing/need a clean?

Help would be extremely appreciated, it's starting to drive me nuts!

Postby **NitroDann** » Tue Sep 10, 2013 6:33 pm

It sounds like it could be a locked diff.

Do you hear the tyres? If a bystander watches the wheels do they turn normally?

Dann

slimx · Postby **slimx** » Tue Sep 10, 2013 6:46 pm

this might sound dumb but i ran into this once, and just tightened up the bolts around the rear (the arms, suspension etc) and it did the trick

euph0r1a · Postby **euph0r1a** » Tue Sep 10, 2013 6:52 pm

Slimx, I'll definitely try that. Should be able to get under the car on Thursday and have a poke around.

Dann, I got my housemate to take a look at the wheels, they go from full lock to full lock fine. One thing I did notice though was when I hit full lock either left or right, it sounds like gas escaping/fluid running. Power steering? It stops as soon as I let off full lock.

Postby **NitroDann** » Tue Sep 10, 2013 6:57 pm

That sound is power steering, I meant do the rear wheels turn like they should when turning very slowly at or near full lock.

Dann

euph0r1a · Postby **euph0r1a** » Tue Sep 10, 2013 7:00 pm

NitroDann wrote:I meant do the rear wheels turn like they should when turning very slowly at or near full lock.

Dann

Duh, that makes more sense! I'll have to find a friend and some space to take a look soon.

JBT · Postby **JBT** » Tue Sep 10, 2013 8:18 pm

euph0r1a wrote:Car starts up first time, every time, but occasionally does emit a high pitched squeal for a few seconds coming from towards the front of the bonnet, which then disappears and doesn't happen again. The squeal probably happens 5-10% of the time when it's turned on, usually when the wheel is already turned........Possibly the power steering? Because it only happens when the power steering would be in use, and from a bit of reading the power steering belt could possibly be loose.....

I think you may have answered your own question. Check power steering fluid level, accessory belt wear, tension, and power steering pump in that order.