Another chuffing noise

Another chuffing noise

Author
Discussion

adam quantrill

Original Poster:

11,538 posts

243 months

Thursday 10th May 2018
quotequote all
Mr Tank said:
A1 Gearboxes in St Neots, they have rebuilt three LSD diffs out of wedges for me.

It didn't cost a lot....
Possible, and not that far out of my way.

What was the average price?

adam quantrill

Original Poster:

11,538 posts

243 months

Monday 14th May 2018
quotequote all
Cheers Andy,

well I have it sully apart now and even have the front bearing shells out, it isn't that hard to work on, just a matter of putting it back together now with some new front bearings.

I must say that I've heard tell you can replace the front oil seal with the diff on the car, I actually found this one of the trickier things to remove, I had to make a puller to pull it out using the front bearing (that I was going to replace anyway.

I'm pretty sure now that the front bearing has been causing the problems including the "steering left noise disappearing" phenomenon. I could see some evidence of asymmetric wear. I wonder if the wedge propshaft geometry could contribute, where the jag input shaft is offset from centre whereas the gearbox output is on the centre line.

adam quantrill

Original Poster:

11,538 posts

243 months

Monday 2nd July 2018
quotequote all
Well despite the obvious fault with the diff pinion bearing the same noise is still there with the replacement diff in place.

I suppose on the good news side I have caught the diff before terminal failure, I've flushed the rear brake fluid where a seized bleed nipple would have thwarted that job, and the handbrake mechanism actually works properly now. Plus I caught some corrosion on the back chassis just in time.

The old diff will be reconditioned when I have some more time but for now back to the noise.

- I've bought a contact microphone I can clip onto various parts to help narrow down the noise source while driving along. It plugs into one of the boys guitar practice amps. It should at least tell me which corner it's coming from!
- I spotted a UJ was a little loose so have some replacements ready to go on. Even though it's not usually this sort of noise that it causes but I'm scraping the barrel now.
- The nearside rear bearings have a grease nipple fitted and are re-greased, will do the other side next (had to order another 2.5mm drill bit)

adam quantrill

Original Poster:

11,538 posts

243 months

Saturday 8th September 2018
quotequote all
Some progress today with the noise. I have rigged up a coax cable to the underside of the car with a 1/4" jack so I can plug it into a battery powered guitar amplifier.

Under the car on the other end is the contact microphone.

First clipped it onto the offside diff carrier. It was a bit noisy but didn't seem unusual and no whirring noises. Turned down the volume control to set the gain.

Then I moved the mic over to the other side - it was like night and day! Massive whirring noises, that alter on cornering too.

The odd thing is the bearing is quite quiet when the wheels are off the ground, and it has ho play. This is what has been putting me off diagnosing the fault.

Looks like I have a new diagnostic tool....

adam quantrill

Original Poster:

11,538 posts

243 months

Sunday 9th September 2018
quotequote all
Yeah I've had a few go in the past and they usually get very sloppy. This one is still tight and also the hub nut is still f**** tight - so tight I couldn't break it last time I tried. I might take the split pin out and see if it starts to free up with some driving.

adam quantrill

Original Poster:

11,538 posts

243 months

Sunday 9th September 2018
quotequote all
Some good news at last - took out the split pin and had another go at moving the nut, this time with wheel on and handbrake on, in gear and chocked.

After bending a 1/2" drive bar I joined the breaker bar to it on both sides of the bar adapter, and after bening my breaker bar in the middle, it finally moved.

Also in another stroke of luck I found out one of my son's rugby team dads owns a garage with a couple of presses and negotiated having the bearing pressed out and back in.


adam quantrill

Original Poster:

11,538 posts

243 months

Saturday 22nd September 2018
quotequote all
Well my hub had been pressed, new bearing in, off to collect it this morning.
Also new HT bolts are here so I have the full set for replacing any others that go, but I will be doing just the 5" one as the 6" one was done last year anyway.

Hopefully it will all go together without a hitch, plenty of grease in the bearing, and we'll be back on the road. About time too!

adam quantrill

Original Poster:

11,538 posts

243 months

Monday 24th September 2018
quotequote all
Drove to work today, first "whoo hoo hoo" moment for months when I hillclimbed up Madingley hill in first then second. We have so few hills around here!

Bearing is now quiet, whirring noise gone.

THe old one must have had water ingress through the seal as thre was some mucky rusty looking grease in the inboard side.
The old style seals are solid rubber and once they wear they lose sealing ability, the new style ones have a metal spring inside the lip to keep them closed on the shaft for longer.

Nothing in the old bearing was actually broken, which is why I didn't diagnose it for so long, it wan't flopping about or getting loose.

Only problem is, now the whirring noise is gone, I can hear all the other squeaks and grinds when I put the power down!


Edited by adam quantrill on Monday 24th September 20:49