26 replies to this topic

[BUT83]

Hi, I have a feeling I am being really daft but hopefully someone can restart my brain. I have converted my 1983 city E front drum brakes to disc with a kit from mini sport. However the wheels are no longer aligned correctly, the toe is too much , I presumed the geometry would be the same on drum and disc hubs? So have I done something daft or should I go ahead and adjust the steering tie rods?

Many thanks.

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[Swift_General]

Yes you need to check the tracking. But you can't just do it by eye though.
One of your brake hoses looks very twisted by the way. May need rotating at the subframe end.

Edited by Swift_General, 26 February 2017 - 05:23 PM.

[tiger99]

Did you check that the two hollow dowels were fitted around the bolts on each steering arm where they attach to the hub? They are absolutely essential and without them the toe will keep changing until something breaks.

Also the hubs may have been designed for different Ackermann angle, which would change the angle of the steering arms and so affect the toe. Not necessarily a problem, but it might be if the handling turns out to be poor or you get bad tyre wear in tight turns.

Are you sure that you do not have Metro hubs? These are geometrically different to the Mini, and have unsafe effects on the handling due mostly to scrub radius and KPI8 differences. They must not be used. The differences can not be corrected by adjusting toe, castor or camber.

If all of that is correct you just need the track to be adjusted properly. If it involves unscrewing the track rod ends too far, perhaps because of other changes such as negative camber, get a pair of Triumph Spitfire/Herald etc track rod ends, which Mini suppliers will overcharge you for as compared to any Triumph supplier or even the likes of Euro Car Parts. They are longer, and if you are lucky may even come with a grease nipple to help longevity.

[nicklouse]

check your steering arms against the drum ones they should have the holes in the "same" places. if the TRE hole makes a different angle then you have incorrect arms for your car and you need to get the correct ones.

 

you can use your drum ones for now but I would change then before you get on the "track".

 

also note you should have lock tabs under the bolts arm-hub.

[tiger99]

You are correct. I was unable to view the pictures properly earlier. There do need to be lock tabs. Also, it may be hidden from view, but I can't positively say that the lock tab for the ball joint has been flattened against at least one face of the nut. Makes me wonder even more about the dowels...

[BUT83]

Many thanks guys.
I will check for dowels on the steering arms and if that fails I will swap the arms from the original drums.

I checked the invoice and it says Mini Cooper s 7.5" disc brake assembly

I am unclear what you mean by lock tabs under the bolts arm hubs, do you mean lock washer on the swivel hub ball joints? I have attached a bigger image.

Cheers

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[nicklouse]

The ball joint lock tab has not been turned up as per your manual.

Lock tab under steering arm bolts is missing.

As already stated take one arm off and check against an existing one from your drum set up.

Actually check both as you best not presume anything.

[GraemeC]

There is no difference between arms for drums and discs, same part. So unless your originals had got bent, then the new ones will make no difference.

Do check for the presence of the dowels though and also that the bolts are the correct ones with a plain shank of sufficient length to reach well inside those dowels when assembled.  Also ensure the bolts have some form of locking - lock tab or thread lock. 

 

Did the hubs come ready assembled from MiniSport?  If so then they are very poor not to have had the ball join lock tabs turned up and that would lead me to want to check everything else!

 

 

But at the end of the day, the difference in tracking is not something I would be to shocked at.  I would not expect to fit two complete new hub assemblies and not need to redo the tracking - the tolerance build up is very large.

[tiger99]

I agree, a small difference in tracking occurs when you change almost anything in the steering or suspension, and it is usually sufficient to merit adjustment by your local tyre dealer, who are usually the cheapest. I was under the impression that it was a bit more than that in this case, which is why I questioned the actual angle that the arms are set on the hubs, due to how they are machined, as well as possible loose or missing dowels. Some cars had slightly different arms. Cooper S and 1275GT, 1963-74. Unlikely to be the problem in this case.

 

The bolt, locktab and dowel are items 21, 22 and 23 in the link below.

 

http://www.somerford...page=page&id=52

 

Regarding the ball joints, they are worrying me. Why were the lock tabs not done up? Have they been shimmed correctly, or have the nuts just been nipped up? I never trust anything like that unless I have done it myself. I would suggest undoing the tapers and checking that the large dome nuts top and bottom are torqued up correctly, and that the joint will move freely through its full angular travel. If not, take them back to where they came from and demand proper replacements or a full refund.

[Cooperman]

 What is worrying is the ball-joint lock tabs have not been 'locked' into place and the lock tab under the steering arm to hub bolts has not been fitted at all. It can be acceptable not to fit this lock tab under the bolts, but flat washers MUST be fitted and the bolts must be installed using the correct grade of Loctite. This is normally done where the arms may need to be replaced more frequently (for example for competition where the arms can easily get bent). For a road car the lock tabs should be fitted, the only other alternative being properly done wire-locking.

[BUT83]

Much appreciated advice. 

 

Yes because it was pre-assembled I didn't think to check the swivel hubs, another lesson there. I had to send one of the calipers back as it was faulty.

 

Yes they say on there website to fit the locking washer to the steering arm but they have used spring washers, is this acceptable? Can i also check that on the track rod bolt that goes through the steering arm there is no washer which also doesn't seem right?

 

Looking at mini spares web site there seem to be two different part nos for steering arms BTA894 for cooper and BTA896 for others but as you say they should be the the same angle.

 

So I will check everything as you have detailed above.

[GraemeC]

There are 2 different steering arms in terms of geometrey:

Mk1 - 21A73 and 21A74

Mk2 on - BTA896 & BTA897 

 

Then there are CooperS/1275GT versions of each which are stronger

Mk1 - 21A1464 & 21A1465

Mk2 on - BTA894 & BTA895

 

Your car will NOT use the Mk1 arms (or steering rack).

 

 

 

The spring washers are a poor assembly - they will lift the bolt further out of the dowel than it should be. I would replace these with locktabs (part number 2K5377) and retorque.

 

 

 

No, there is no washer on the track rod end, just a nylock.

Edited by GraemeC, 28 February 2017 - 01:56 PM.

[Cooperman]

As Greame says, do not use spring washers for the steering arm bolts.

 

I always fit a thin flat washer on the track rod end under the Nyloc nut. Remember, never re-use a Nyloc. They are 'single-use' only. If stuck and you don't have a new Nyloc, take the old one, lay it onto a flat surface and give the top of it a thump with a hammer. That works until a new nut can be fitted, but it's not ideal.

[tiger99]

Generally, spring washers are not useful on the most highly stressed and torqued bolts, as the washers tend to fracture and be expelled from under the bolt head. There are at least two grades of spring washer, one is thicker in the radial direction which gives more bearing area and better ability to resist radial expulsion, but not so easy to buy. I agree that they are not appropriate on these places we are discussing, however two spring washers of the thicker grade are normally supplied with the top and bottom ball pins and ought to be used there, although Nyloks and flat washers might be better if there is sufficient thread protrusion to fully engage the Nylok. Actually, from memory, Unipart ball joint kits used to come with Nyloks.

 

I always use locktabs where they are intended to be used, even knowing that Loctite of the correct grade actually gives greater structural integrity, because the locktab can be SEEN and VERIFIED by yourself, as a check that you have done things up properly, and by the MOT tester. You can make up locktabs from offcuts of sheet steel if none are immediately available. Zintec sheet is ideal as it tends to resist corrosion. Stainless locking wire is very good, as all the aircraft people here will surely confirm, but drilling the corners of the bolt heads for it is a right pain without suitable equipment.

 

I sometimes have used a flat washer on the track rod ends, to help the nut to be torqued up cleanly against a smooth surface. The end of the steering arm invariably has machining marks which impede free rotation and may result in less tension than you should get for the applied torque. Not that the taper is likely to work loose, but force of habit on high quality work dictates a hard flat washer. Same with cylinder heads and such like.

[Magneto]

Just be sure if you use a flat washer under the nut on the track rod that the hole is large enough, you don't want it to bind on the taper and keep the nut from tightening properly