Caliper not aligned to disk

[HumBuck]

Hello All,

A little help if you please.

I am in the gradual process of building up a Spyder chassis for for my 71 +2 S130 but have come to a grinding halt.

All looks ok, but when I try to fit the caliper onto the Spyder hub carrier the disk fouls the inside of the caliper. I reckon it's off by about 3mm.

It's the same on both side.

Here's a pic showing the large gap to the left of the disk and no gap to the right:

(forgive the rubbish caliper paint job!)



Spoke to Spyder and they said that have seen cases where the faces of the drive lugs have been machined back resulting in a misalignment. I don't have a reference piece to hand but mine are a nice square half inch so I suspect ok:



This made me think that perhaps I had not pressed the axle in all the way, but I can't see how it could go any further. A precise 2 inch protrusion makes me think all may be ok:



Likewise, a exact 1 inch gap from the drive lug to the caliper looks like it may be correct.



But alas it can't be. Something has to be out and I just can't see what.

If any one has a successfully assembled chassis to hand, it would be great to know how my measurements compare.

Thanks,

Humbuck

[Grizzly]

I had a similar issue but using stock hubs etc, seems i got a pair of badly machined disks that had me scratching my head for a while...... mine was only 1.5mm out of wack but it meant it was almost impossible to make the hand brake work correctly.

[LaikaTheDog]

Is your picture upside down?
I think shims between the caliper and mount will centralise the disk.

[HumBuck]

Thanks for replies.

I happen to have two different disk parts available to me with no variation so suspect disk is ok.

Parts are mounted in vice so will appear upside down.

Was trying to avoid shims if I can, but may have to accept for now.

Best guess is that there is something wrong with the bearing configuration - wrong parts, wrong way round etc. But would need a measurement from another set up to confirm.

Thanks

[Craven]

Not sure if it applies here but the usual problem is the inner hub bearing has been fitted the wrong way round. The small shoulder on the race should be on the inside,that is on the hub side away from the spider.
The Spyder hub has two circlip grooves for the back of the bearing are you using the correct one, this is done to take the wide or the narrow bearings.

[MarkDa]

If the disc runs true then it must be caliper misalignment?
This could be overcome by spacing the caliper - however this shouldn't be necessary.
It's not the first time that Spyder point the finger everywhere except their own fabrication.

[RichardHawkins]

Humbuck,

I have just taken the body off the chassis again. I can confirm that the 1/2" dimension is the same on my car, but as the hubs are on I cannot check the 2" dimension. I am also using Spyder struts.

Hope this helps,

Richard Hawkins

[mark030358]

My 2p worth...

If the inner and outer circlips fit, and the small one on the stub axle is in place then the bearing fit is correct. My reasoning is that the inner bearing is pressed onto the stub shaft and the small circle fitted. Then the shaft, housing and outer bearing are mated/pressed together (you know what I mean) and the two large circlips fitted. If the circlips are located then the bearings are properly located too.

I would guess your disks are out of true. i.e. where there are machined to mount onto the drive shaft. I would check this measurement with some old disks.

cheers
mark

[vincereynard]

It's not the first time that Spyder point the finger everywhere except their own fabrication.

It does seem their first general response.

If the shafts are OK and, if all the circlips fit, they must be. Then the Spyder uprights must be a suspect?

My car has them and I'll be replacing them with rebuilt Issue 18s shortly. Anything you would like me to measure?

[Craven]

Mark030358
Clearly I don?t know how many rear bearings you have replaced but my guess would be none.
Take a look at this pic, the bearing is not symmetrical so if fitted incorrectly it will position the shaft relative to the hub in a different position.

img_4445.jpg (60.18 KiB) Viewed 1465 times

[HumBuck]

Thanks for these responses chaps. I?m away at the moment but back tomorrow so will have another look and post back then.

[Donels]

I had exactly the same problem. It turned out to be two issues. 1 was paint on the mating faces of calliper and hub, paint removed to bare metal. Second was runout on the 3 legs. They were all the correct thickness but not all in the correct place, to misquote Eric Morecambe. This was solved by using thin stainless shims between the legs and disc to get it true and it the correct place. It takes a lot of trial and error to get it right.

Dave

[mark030358]

Mark030358
Clearly I don?t know how many rear bearings you have replaced but my guess would be none.
Take a look at this pic, the bearing is not symmetrical so if fitted incorrectly it will position the shaft relative to the hub in a different position.

img_4445.jpg

A few to be honest, but your sarcasm is appreciated.

Obviously I've not fu*ked one up or fitted one as shown in your picture. The intent of my post was to imply that a square fitted bearing correctly located should not affect clearanc, but that a badly machined brake disc on the other hand will. Please ask me how how I know.....

thanks

[JonB]

That's actually one of my pictures chaps..

The bearing on the right is as it came off the car (passenger side rear outer shaft, inner bearing if that makes sense). I still have it as shown, because the shaft was ruined by the outer bearing. It'd worn a big fat groove in the shaft which was causing the issue I'd gone in there to solve - knocking sounds on bumps. I had to buy a new shaft in the end.

Reading this thread I begin to feel very fortunate that it fitted together correctly..

[69S4]

the shaft was ruined by the outer bearing. It'd worn a big fat groove in the shaft I had to buy a new shaft in the end.

I've had two shafts do that in the time I've owned the car (since early 80's). I assumed it was caused by the bearing inner race wearing the shaft away but why, with a new shaft and a new bearing (in the second case), should that happen? The first shaft was worn when I bought the car but the second one was all new parts (and years of use).