MOT FAILURE!!! (and LSD question)

[lee bishop]

my car failed its mot today, nothing bad, a steering rack boot was split, and both lower rear shackle bushes are worn..... i have tried to get the local ford dealer to source some replacement bushes, i dont want to fit poly bushes so i'm keeping it stock......for now. i'm just after any other possible sources for bushes, incase the dealer comes up with nada! burtons dont do them, nor do local motor factors.....any other ideas people?
secondly, the bloke doing the mot said i had a LSD, but i didnt think i did! when the car is jacked at the rear, and one wheel is turned, the other goes in the other direction, (after a little back lash is taken up) but i thought that both wheels would rotate in the same direction if i had an LSD?? can anybody confirm this please, is the something on the chassis plate that will state if an LSD was fitted at the factory???


cheers in advance........lee

[RS2000&MEXICO]

kevin curtis has got some lee..

[M11RF]

You can get poly bushes that look std-ish Lee. All in black.
I could have sent you my old ones but they are long gone!!
They were ok too :violent1: sorry!!

[Kel]

I'm sure burtons or rally design do new items

[lee bishop]

not an issue of looking std, you shouldnt mix poly and rubber bushes, and i dont want to have to fit polys everywhere, just cos two have gone crumbly, what about the LSD issue, no one has answered that one.....

[Tim]

sounds like u got a lsd

[RS2000&MEXICO]

do a nice big wheelspin lee ... if there are two black lines left behind then you have got a lsd if only one then its standard thats the way i test to see if there is a nice lsd in the axle.... :cheers:

[lee bishop]

anybody got any more bright ideas?

[RS2000&MEXICO]

whats wrong with that lee.....lol

[lee bishop]

nothing if you dont care for your car......lol

[RS2000&MEXICO]

allright then just do a small wheelspin then

you know you want to.....pmsl

[lee bishop]

i have a standard engine, with 7" wheels! it doesnt wheelspin! it just goes....... only in fast corners does it let go

[M11RF]

Shamelessly stolen from TurboSport and passed off as my own work!! hehehehe... :laughing6:

No need to elaborate on that bit, Gary was spot on. A full locked diff, i.e. welded up would in effect be 100% LSD - but its not actually an LSD then so to call it a 100% LSD is a bit confusing for my little, slightly pickled brain.

Imagine this, youve got one wheel in the air (no grip at all) and one on the ground with lots of grip. With a free diff (i.e. not an LSD, or 0% LSD) All the drive would go to the wheel in the air. With a (metaphorical) 100% LSD - then both wheels will turn the same amount - even though one is in the air.

Theres loads of other variables with an LSD though - preload for a start - this is how hard the clutch plates are pressed against each other when at rest, so even when you are driving in a straight line, there is some load on the plates. This is adjustable by fitting stronger springs, and/or fitting thin shims behind the spring to compress it more. You know how most people check for an LSD - jack the wheels up and see which direction one wheel turns relative to the other? Well what you are actually checking is pre-load - if it didnt have any preload, the other wheel would just stay still, but its still and LSD. This is not the same "preload" that holds the taper roller bearings in contact with each other. Typically, a gravel car will have higher preload than a tarmac car.

Incidentally, automatic torque biasing diffs dont have any preload (they dont have any clutch plates actually) - they work on a different principle, and progressivley wind up as you go round a corner. I have to admit i don't fully understand them, but to be honest i don't plan on using one either so it doesnt really matter!

Then you've got ramp angles - the "V" shaped groove in which the sun pin's ride. Typically these are a 90% groove, i seem to remember - which means you have a 45 degree ramp angle for braking, and the same for acceleration. To get an idea of what the ramp angle does, think about rolling a log up a hill - the steeper the hill, the harder it is to push, therefore you need to get a bigger torque gap between the 2 wheels to get the sun pin to ride up the ramp and start pressing the clutch plates together... This feature is not exactly adjustable - unless you start machining out the ramps, which is a whole new ball game.

Just to complicate things a little bit more... anyone ever used a "detroit locker"? Exact opposite of an LSD - it is locked when you go in a straight line, but frees up when you go round a corner. Dragsters are about the only thing that would use these, unless im mistaken.

So what diff should you be using on the road? If you are arsing about doing donuts, and/or going round roundabouts backwards then you will find a standard LSD not quite up to it, i would suggest. However a full-on gravel spec rally LSD will clunk and bang and generally make the car a bitch to drive round town, not to mention make it understeer. So really you want something in the middle. Our rally car has what i would describe as a tarmac spec LSD - full set of plates but not too much preload - and it is perfectly civilised on the odd occasion its used on the road.

Right i'm sick of writing, any more questions just fire away, i'll try my best.

http://forums.turbosport.co.uk/bbs/showflat.php?Cat=0&Number=329551&an=0&page=0#329551

[lee bishop]

i am no better off mark.......wheres that whisky...... :drunken:

[M11RF]

Looks like you`re going have to get the spanners out and take it to bits mate... Dont ask me how you tell when its out though!! :laughing6:

Brian, or should i say Brain... Will come up with the answer i`m sure ;)

[lee bishop]

can you tell by just looking at the case of the diff?

[M11RF]

No mate... i know that much.

[RS2000&MEXICO]

dave will be your man when he comes on...

[lee bishop]

come on, i gotta go out on the razz in a bit......... brain?? dave???

[Banishit]

whos Brain ?

if you ment Brian LOL I know nothing about them, I know what they do and what there for :geek:


I though the way to tell is jack the back end up and turn one wheel quickly and if the othersides wheel goes in the opposite direction its a normal one

or jack one wheel off the ground and try and turn the wheel quickly if it starts to bind theres a LSD in there

[martin c]

If you jack the car up and one wheel spins the opposite direction
to the other it means there's no lsd if it spins the same way
you've got a lsd :cheers: :cheers:
Hope this is of help

[Roger Miller]

the bloke doing the mot said i had a LSD, but i didnt think i did! when the car is jacked at the rear, and one wheel is turned, the other goes in the other direction, (after a little back lash is taken up) but i thought that both wheels would rotate in the same direction if i had an LSD?? can anybody confirm this please,

No not limited slip.

This is what happens with STD diff.

and

U need a new service guy, cause he should know!

[Roger Miller]

A plate type diff...............

http://img.photobucket.com/albums/1003/RNinOZ/Diffs/trdlsd2.jpg

As opposed to a worm gear diff....................

http://img.photobucket.com/albums/1003/RNinOZ/Diffs/trdlsd.jpg

Looks like this, for a English axel............
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/Diffbits-Named.jpg
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/Diff_rebuild_3.jpg
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/Diff-_sllipery_exploded.jpg

A "plate diff" is "shimmed up" at assembly time so that it gives at least 50LBS of break away torque, when tested.

This means if a torque wrech is use on a left axel center and the right axel is held, the reading on the wrench should be 50lbs. etc.
Incidently, note these diffs have 4 "spider Gears" fitted. The STD units have 2. No doubt, those who have broken a diff will recognise this.

The "Ramp Angle" , on internals, can also be varied.
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/diff_ramps.jpeg
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/Tran-X-English-Diff.jpg

This provides a way of varying the lock up, when driving car.

A car needs little or no lock at corner entry, but a higher percentage when leaving it.

Next the plates them selves can be stacked differently to provide differing lock up "attitude"

http://img.photobucket.com/albums/1003/RNinOZ/Diffs/Locking-Diff-Platepairing-1.gif
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/Locking-Diff-Platepairing-2.gif

Also,people overere are trying to make the gear type adjustable.
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/Diff2-M.jpg



Overere, the axels vary abit.
1600cc cars have better axels.
U can see the axel reducion area.
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/2litre_1600-Axles-Merge.jpg

[b]The very early diffs had a cast steel end plate. these Need to shimmed up LESS due to their de-creased strength.

Steel ones are machined all over.
http://img.photobucket.com/albums/1003/RNinOZ/Diffs/LSDEP1-End-Plate-Steel.jpg

Take it easy

[dasadrew]

This is a bit embarassing but.....

There have been a couple of posts recently that say if your backend fishtails off roundabouts etc. - you need an LSD!

Up to now, I had thought that if you're going round a corner a bit too fast under power, and you HAVEN'T got an LSD, then the power to the road will drop off 'cos the inside wheel has lost grip and one wheel alone can't drive the car. This would mean that the car generally gets slower, and the situation sorts itself out.
??

With an LSD, the power to the back wheels can be maintained and they give you permission to get into deep sh it!
??

I would have thought an LSD on a roadcar would just allow a non-professional to get himself into trouble.

I thought the idea of an LSD was to enable a professional driver to keep the power on. Indeed, on a special stage start on mixed surfaces, I would have thought the "fishtailing" which some posts think will be cured would actually result by having an LSD whereas a non-LSD would just fizzle out when one side got into mud.

(All of the above is with the exception of LSD's on roadcars in southern Germany when you have them simply to get grip at all on snow and ice)

[yellow peril]

Lee
I have some rear shackles bushes, genuine ford rubber ones, if you dont get any joy anywhere else.
Happy to let them go to a good home, i am polybushed through out so dont need them.

[lee bishop]

cheers yellow peril! my ford dealer assures me some will be in stock tuesday, but there is still a chance they have ordered the wrong item..... i'll let you know

[yellow peril]

no problem mate

[lee bishop]

sorted my steering rack gaiter today, thats fitted and im happy, i also got my bushes from my local ford dealer, and they are not what i expected, they look the right size, but the section of bush that fits into the rear leaf aperture is triangle shaped?? is this correct?? the part number of the bush is 75AB 5719-AA L&H25 somebody please tell me i have the right bushes before i take my car apart......

[RS2000&MEXICO]

thats spot on lee thats how they are m8.... :cheers:

[lee bishop]

phew......!

[lee bishop]

is there a specific way they should be orientated? point up or down or doesnt it matter?

[RS2000&MEXICO]

it don't matter lee just push them in.... :cheers:

[lee bishop]

will i have to remove the petrol tank to access the offside spring shackle top nut??

[RS2000&MEXICO]

you got it in one m8 nice job that will be for you

hope you don't find any rust..... :blackeye:

[lee bishop]

no, the tank was taken out last summer, and all the rust was sorted then, better not be any, that work cost me a bit........

[RS2000&MEXICO]

good luck with it then lee hope you don't find any..... :cheers:

[lee bishop]

i did the bushes friday afternoon....piece of cake i tell ya, never had to take the tank out..... and they all went in easy peasy. took the car back to the garage, and now im sporting nearly 13 months MOT, pity its going to be SORN'd for the next three months...... :banghead:

[dasadrew]

Nowt like a bush Friday afternoon after work!

[lee bishop]

i banged two bushes mate.....

[dasadrew]

Did you have to use vaseline to get the bushes to fit?

[lee bishop]

silicon grease i used.........so sort of.....yeah!