Ill fitting wire wheel hub.

[Ian Hastings]

I'm having problems fitting a rear wheel hub for wire wheels so I'm hoping someone can help out please.
When I fit the brake disk to the hub and fit it to the driveshaft there is insufficient clearance to fit the brake caliper. I have measured it roughly and it would appear the disk is 4mm too far outboard to give clearance to fit the caliper. The old steel wheel hub was fine and the hub on the other side fitted OK. I have fitted the hub with and without the key, looked for burrs preventing proper seating etc. etc. but cannot find anything.
Short of fitting spacers between the new hub and the brake disk or grind huge chunks off the caliper casting, I cannot see how to get round it and I don't want to do that for obvious reasons.
I have contacted MWS the suppliers who suggested asking Daimler 'experts' so I'm hoping some experts are reading this!

I suspect the hub will be going back to MWS in the near future.......

[silverdart]

Ian, How about fitting a spacer between the calliper mounting flange and the inner face of the axle tube flange?
If I have understood your problem correctly , that should work I think?

Dave.

[Ian Slade]

From what I remember you can only space the caliper inwards, the caliper bolts to the axle from the inside of the axle, the caliper mounting is not reversible, if it doesn't fit then the drum or hub is incorrect, if using the original drums then the hubs are incorrect. Have the hubs been modified from another car or are they a re-manufacture?

[Vortex O'Plinth]

4mm does seem a long way out. I assume the axle bearing shims have not been altered during the swap from pressed wheel hubs to wires?
Have you tried fitting the offending hub to the other side of the axle? I know it's the wrong nut thread on that side but the hubs are interchangeable and if the same problem is encountered, and since the 'correct' hub on that side was OK, the problem must reside in the new hub. The calipers can be shimmed to position them symmetrically around the disc, but as Ian states, by adding shims they can only be moved inboard.

Once the cause of your gross 4mm error is sorted it's worth noting that the position of the the brake discs relative to the calipers can be balanced side to side. The half-shafts butt on their inner ends against a spacer which is free to float laterally within the axle, so provided the total number of shims necessary to achieve the correct hub bearing end float is maintained, the complete half-shaft/hub/disc assembly can be moved laterally within the axle by removing shims from one side and adding them to the other. This can help to ensure that both calipers can be fitted symmetrically around the discs with appropriate shimming.

[silverdart]

As Nick Says, there is a spacer in the middle of the diff., but I have just measured one and the total float possible is only .160in.
So it is unlikely that will solve the problem.
Could it be that there is already a spacer fitted between the calliper bracket and the axle flange?

Dave.

[faeton]

When I bought my car many years ago it was in pieces , the previous owner had overhauled the back axle . The car came with new callipers . when I tried to fit these I found a similar problem . I thought the calipers could be the wrong ones . I thought of machining some metal or spacing , As I had found some other items bodged by the previous owner I decided to strip the axle and reassemble myself . Good job I did he had put the outer rear wheel bearings the wrong way around , This would have meant that the thrust side would be the wrong way . I correctly assembled and the calliper fitted.. Probably not your problem as your ordinary hubs fitted but with cars of our age nothing can be taken for granted.

Dave

[Ian Hastings]

Thanks for all the replies.
The wire wheel hubs are brand new from MWS (Motor Wheel Services) and the port side one fitted as it should but the starboard one is the one which is not correct.
The calipers on my car never had shims fitted, at least in my time, and they were centered satisfactorily. As the port side is fitting OK I do not see any point in disturbing the wheel bearings and their shims to try and balance things up. The port caliper is fitted and I really could not be bothered dismantling it all again although I suppose I should to compare the dimensions of the two hubs just to see if there is any difference.
Ian is correct in saying that the caliper can only be shimmed inwards but I need the caliper to go in the opposite direction.
Tomorrow is another day so the suspect hub will be dispatched back to MWS for replacement. I will report back later.
Many thanks again.

[tjt77]

Ian, did you measure the dimensions of the 'other' hub that actually fit to compare with the one that does not ? I'd think this would give some answers if there is an actual difference in any of the dimensions..

[Ian Hastings]

No I didn't because the other hub is now fitted and I really can't be bothered taking it all apart again however I will measure the 'faulty' hub against the old hub that I took off on the bench.
I did measure the differences with the old and new hubs fitted and the difference to the fitting surface for the disk for both was about 4mm.
I had hoped to do it all today but I spent 8 hours in eye casualty getting an eye problem investigated, thankfully nothing sinister found.

[Ian Hastings]

At last I have resolved the ill fitting hub/caliper problem so posting an update as promised.
The suppliers of the hub sent me three different hubs but all failed to fit properly so I removed the caliper mounting bracket from the axle and milled 3mm from the surface to which the caliper is mounted.
This allowed the caliper to be fitted satisfactorily with the hub in position. However when fitting the hub castellated nut onto the halfshaft end it would not go on far enough to allow the split pin to be inserted so I had to turn about 3mm off the fitting surface of the nut to allow it to go on further.
So effectively the taper in the hub had not been opened out enough for normal fitting. Anyway, problem solved.