Another knocking thread

[gymmaniac]

A new unidentified knocking on my 110.

This time somewhere in the rear drive train.

Fast moving no problem. Under power, no problem.

Slow moving in traffic then quite a loud thudding. It's easier to make it happen if driving with the clutch down going slowly.

I've only just had an MOT and they tightened up the hand brake. I thought it may be slightly coming on or something so had a rear wheel jacked up earlier and span a rear wheel but every thing seems fine:

Both rear wheels have no play / bearings look ok.
Prop shaft seems ok.
I replaced the A-frame pivot a couple of years ago. Occasionally now it does give the knock stopping/starting which could be the pivot going again but I can't see it making the recurring thud-thud-thud I get while at constant speed.

Any idea what I should be investigating next?

cheers

 

[nobber]

A frame ball joint should last more than a few years, mine has been in there a good decade or so, you need to go through the drive train, it could be any number of things, drive train shunt isnt difficult to get to the bottom of.

 

[gymmaniac]

I've just had another test drive, it's definitely towards the rear diff.

Handbrake on, one wheel off the ground I can turn the wheel around 15 degrees between the prop shaft starting to turn. I'm leaning towards lots of slack in the diff so there's juddering when the rear wheels and prop speed are around the same speed when I'm stop/starting.

 

[1988smithy]

I had similar, new rear halfshafts and flanges sorted it

 

[gymmaniac]

I replaced the rear half shafts and HD drive flanges in the summer.... worth taking the caps of and checking though I guess.

It's not the stop/start thudding. This is a repetitive thud,thud, thud etc when the rear isn't quite under drive.

 

[nobber]

If its repetitive its not drive train shunt, its not slack, slack in the final drive unit like you describe is normal.

 

[Rougharse Racing]

I would have another look at the rear prop, try with one wheel off the ground so the prop isn't under load, which may mask wear.

 

[gymmaniac]

The garage would have removed one end of the prop to do up the handbrake drum so it wouldn't surprise me they'd buggered up something. What kind of wear should I be looking for?

When I rotate the rear prop (wheels on the ground) should I see any movement of the diff oil seal flange moving in/out of the diff housing?

 

[Rougharse Racing]

The prop wouldn't have to come off to adjust the hand brake.
The diff flange shouldn't move in and out , it may be that the pinion bearings are worn, could be worth checking that the nut holding the flange on isn't loose though.

 

[mick 1986]

The garage would have removed one end of the prop to do up the handbrake drum so it wouldn't surprise me they'd buggered up something. What kind of wear should I be looking for?

When I rotate the rear prop (wheels on the ground) should I see any movement of the diff oil seal flange moving in/out of the diff housing?

If you grab hold of the propshaft, and try to move it in all directions, up/down, left to right. It should be solid. If you feel any knock, or see any movements between the two yokes, the UJ needs replacing.

 

[nobber]

If you grab hold of the propshaft, and try to move it in all directions, up/down, left to right. It should be solid. If you feel any knock, or see any movements between the two yokes, the UJ needs replacing.

If the wheels are on the ground the prop will be solid anyway.

If you have had work done, and the vehicle came out of the garage like this, bring it back!

 

[nobber]

Oh , and just to be clear, hand brake locks the transmission, not the wheels. A single wheel will spin with the hand brake on. Just adjust the hand brake back a turn. It could well be a tight hand brake and a shoe is rubbing on the drum.

A new unidentified knocking on my 110.

This time somewhere in the rear drive train.

Fast moving no problem. Under power, no problem.

Slow moving in traffic then quite a loud thudding. It's easier to make it happen if driving with the clutch down going slowly.

I've only just had an MOT and they tightened up the hand brake. I thought it may be slightly coming on or something so had a rear wheel jacked up earlier and span a rear wheel but every thing seems fine:

Both rear wheels have no play / bearings look ok.
Prop shaft seems ok.
I replaced the A-frame pivot a couple of years ago. Occasionally now it does give the knock stopping/starting which could be the pivot going again but I can't see it making the recurring thud-thud-thud I get while at constant speed.

Any idea what I should be investigating next?

cheers

​

 

[gymmaniac]

The prop wouldn't have to come off to adjust the hand brake.
The diff flange shouldn't move in and out , it may be that the pinion bearings are worn, could be worth checking that the nut holding the flange on isn't loose though.

Thanks Rougharse (?!), I think this could be a contributing factor and will definitely check.

 

[gymmaniac]

Oh , and just to be clear, hand brake locks the transmission, not the wheels. A single wheel will spin with the hand brake on. Just adjust the hand brake back a turn. It could well be a tight hand brake and a shoe is rubbing on the drum.

Cheers nobber, I'll do that tomorrow evening. I learnt that the hand brake does not lock the wheels the hard way - handbrake turns in icy carpark still means shredded UJ's and destroyed half shafts eventually - I'm sure I'm still paying the price for my innocent fun 9 years ago.

 

[nobber]

Lol, if its hand brake turns you want buy a Mk2 Escort. My guess is when matey did the mot it failed on the hand brake? So they tightened it, retested it but didn't properly test drive it. Back the adjuster right off, dont be afraid to lose the hand brake , test drive it, if its gone you know what it is, if it isnt adjust the brake back up again.
Sometimes with a tight hand brake you can feel a juddering when reversing.

 

[gymmaniac]

I think you're completely right nobber. with a wheel jacked up I could spin the wheel and hear the shoes "shooshing" the inside of the drum. It took another half turn to back off enough to remove the noise. The handbrake now does 3 clicks until tight rather than 1 with effort. Hopefully that will sort this drama.

Unfortunately the ep90 I topped up my transfer box with seems to be mostly around the underside of the vehicle now so definitely oil seals on the transfer box to sort out as a priority. I'm not convinced that the backlash of the rear diff still isn't excessive, maybe a trip to Ashcrofts and a new ATB diff.....

 

[gymmaniac]

Sorted. no more noise and no knocking and all it took was 15 min, a jack and a 17mm spanner - made a nice change to have an easy fix!

Thanks for the help all.