Disc Caliper Alignment

[Peter Truman]

I have as spares fully rebuilt LH and RH Herald front suspension uprights that have Drum to Disc adapter brackets, I have one drum front hub that has been machined at the wheel flange underside to clear the caliper, the other hub is for a Herald early Spit disc set up. Putting Type 14 calipers on the disc hub set up has the disc/rotar running just off centre in the caliper channel/groove a 1mm spacer between the disc mounting flange and the hub rear mounting face is reqd to make it dead equally spaced in the caliper, whereas the drum hub would require a 3mm spacer (drum hub is not as deep as the disc hub, approx 41mm to 38mm).

Question did Triumph make various thickness spacers for the disc rotar to rear hub mounting to get the disc to run dead centre in the caliper groove.

Attached I've included a rough cardboard version of what I think the spacer might look like, I could use washers under each of the 4 disc to hub mounting bolts to achieve the correct spacing but it sounds a bit hillbilly, and unprofessional for something as important as brakes.

I can get individual 1mm and 3mm steel spacer shims as photo made up relatively easy, but was wondering if Stanpart items are available.

[Pete Lewis]

ive been writing to waggner  about a similar problem but he has the felt seal and cup the wrong way round 

seems his manuals show the felt is between cup and bearing    Nooooo!!!!

must be bearing bearing   cup    felt   stub face >-< { |  --|

Pete

[NonMember]

Was it Colin also had issues with a misaligned disc, which was resolved by spinning the hub a few times and re-tightening the nut? For some reason the bearings had not seated correctly on first fitting and needed running then re-tightening to get them properly in.

[Peter Truman]

Pete my felt seal is as you state and whilst newish I soaked them in oil for a few days then compressed them hard with a press for a further 4 days then greased the surface and installed so I’m relatively happy with the seals fitting.

The one with the disc hub is OK just a little off centre but acceptable. The issue re packing needed is the drum hub which isn’t as deep as the disk hub, 3 mm shorter so looks like I try and get another hub (disk) or make a shim spacer.

[Colin Lindsay]

10 minutes ago, NonMember said:

Was it Colin also had issues with a misaligned disc, which was resolved by spinning the hub a few times and re-tightening the nut? For some reason the bearings had not seated correctly on first fitting and needed running then re-tightening to get them properly in.

That's correct Rob; I had bother with new felt seals; too thick and they made it hard to get the proper setting on the endfloat. I had to grease them prior to fitting then fit, tighten, spin a few times, tighten again, and repeat at least once.

I've noticed that on some cars the caliper is not 100% central to the disc but if the hub and disc are correctly fitted to each other, and the endfloat correct on the hub assembly, then the pistons should take up the slight imbalance of a mm or so.

I also had the problem of the caliper scraping against the disc as it rotated, but this was cured by tightening the caliper mounting bolts, which had not yet been done...

 

[Peter Truman]

I've never had to bother at looking at the disc to caliper alignment in the past 58years of Triumphering but because I'm re-coing & using Escort/Cortina Type 14 calipers for the daughters Mk2 Spit I've been checking everything, to make sure their fit for purpose.

Because I only had the earlier Spit/Herald old style uprights with separate caliper mounting brackets here at home and due to the Covid travel restrictions (10klm) I can't drive the 30klm to her place to trial fit, I trial fitted everything on the old setup and ran into problems with one of my reco front suspension/axle sets then found the short drum hub issue, hence the Q re hub to disc spacers & the availability of Stanpart spacers, for fine tuning the disc to caliper alignment. 

[Wagger]

Hi Peter. I had problems getting the disc to run central in the caliper slot on the LH side of my Vitesse. I had a Vitesse RH link and a Spitfire LH one, completely unmatched. I had to source a complete Vitesse/GT6 LH assembly.  The RH side was fine with the same caliper 'Pair' as fitted to the replacement LH Vitesse assembly. The seal wrong way round was not the cause as the bearing was against the rear boss anyway. I have corrected that error. The clue was the actual hub. RH one has a 45 degree flat surface near the caliper, the LH one is radiassed. There were different style hubs for all models, it appears. I had to place 1mm washers between the calipers and the mounting brackets to improve this clearance, and the caliper was fouling on the road wheel. Same mod cured that too. As the bearings 'Bed in' this will centralise very slghtly and the disc will wear and increase the clearance

After much faffing around I just filed and ground every surface that was too close for comfort. All works now so I am just going to live with the 2mm offset. It all works now.

I suspect that the hubs differ +/- 1mm from each other and the calipers will have a machined tolerance too. Nothing is made by the original manufacturers, so errors will stack up.

[Wagger]

In my view, there is nothing wrong with your idea of making a packing 'Shim' so long as it is of made of a hard material uniform in thickness and de-burred. Torque the bolts up diagonally and evenly. You can check the 'Run out' of the disc after assembly.