Judder in reverse gear

[Reg]

Hi I've finally got my Herald 13/60 on the road after a body off rebuild. On going into reverse there is a lot of shuddering. The woodruff pin thing in one of the half shafts sheared during the first drive to get the exhaust fitted properly. This was replaced and loctited in at the garage and I was advised to get a spare halfshaft . The car  still makes some nasty noises on starting off from the rear end. I fitted a rebuilt back axle during rebuild and all wheel bearings, bushes etc have been replaced. Anyone any ideas about the shuddering in reverse ?

Thanks Reg

 

[Pete Lewis]

can start with engine mountings,   diff mounts,  clutch misalignment , bent rear engine plate  puts the gearbox out of line ,

and so on ....can be a long subject , even clutch throw out geometry    its a mine field 

when you say nasty noises is that fwd  or just rev.

Pete

 

[Reg]

Pete, judder is only in reverse and occasional noise in starting off in first gear. This noise  sounds similar to noise when the woodruff key sheared. Thinking about it it could be clutch related as the clutch was seized on and I cleared it by starting it in reverse and clearing it that way. I don't know history of the clutch as it was already fitted by previous owner. The diff is a recon unit.

[Pete Lewis]

Ive never known a diff to create  any judder

The fact that reverse is a lower ratio than 1st that it may be this shows up more as less revs are used in reverse

If the clutch disc damper springs are shot , reveres might show them up where as in first take off is more abrupt and the problem is sort of masked  same applies to bent rear plates , distored over the years of gearbox on and offs the throw   is out of line  and the disc starts to clamp on a small, section not the full diameter

pete

 

 

 

[Reg]

Thanks Pete,

I reckon the clutch will have to come out !

[Pete Lewis]

If the box is coming off sometime do  whip the flywjeel off and check the rear engine plate is actually   ..... flat

Most are awful,  bent from previous levering to remove/refit  the gearbox .

Use a window glass as fairly flat  (dont let the boss see)

Pete

 

 

[Gully]

My GT6 used to judder when reversing - I found the offside engine mount had de-bonded. Having recently replaced it, the judder has gone, so worth a look before you delve deeply unnecessarily.

Gully

[Reg]

Thanks Gully  I will check 

[Pete Lewis]

yes give the engine a lift on a jack , they sit in a Vee so under  weight looks ok , when you apply torque to drive they lift and move 

, this was my first option in the list  ,, beware  many  after market  and repro mounts are really awful and fail very  early  in life 

Pete

 

 

[Reg]

Thanks for that info Pete.....the mountings re ok just checked them . So reckon its the clutch or backplate.

[Adrian Cooper]

Hi Reg,

My Spitfire was off the road for years and juddered when I first put it back on the road. I was getting prepared to replace the clutch but the juddering disappeared all by itself within about 100 miles of use. Maybe giving your clutch some time to bed itself in again, after having been seized onto the flywheel, might save you some work? I hope it proves to be this simple for you.

Adrian

[Reg]

Good advice Adrian, the clutch was stuck on after three years of sitting in my garage so perhaps I should give it a bit longer perhaps it might settle down as you say.

Cheers Reg

 

[Pete Lewis]

you can give the clutch some italian tuning,

drive in 4th gear at 30 mph  then feather the clutch to allow slip and apply all the power you can for about 30 seconds

this re beds the linings , there will be a smell of burnt cardboard , leave the clutch engaged till all cools down 

if you disappear in a cloud of smoke youve gone tooooo far   and cooked it ,

this is a common cure but not for the faint hearted , its a bit crude and rough but can reap great rewards in clutch operation

you need to induce slip and apply power , so some careful foot work 

has to be worth a try 

Pete

[Reg]

Wish I had joined this club three years ago... I could have kept you all busy on this forum with all the rebuild problems  I encountered!!

Thanks again Pete

[Badwolf]

I've been keeping everyone busy (mostly with stupid questions) until you found us!!

[Pete Lewis]

Nothing stupid about the questions ,

Its the drift to stupid answers that keeps us sane 

Pete

 

[Badwolf]

So kind.

[Nick Jones]

If it only judders in reverse and is fine in forward gears then I'd say the clutch is fine and you need to look at the engine and gearbox mounts first.

Nick

[Reg]

Thanks Nick, I'll give the mountings a closer look. Been busy with other things so havn't got back to the problem yet but now got lots of leads to try as soon as I can get back in the garage!