22 replies to this topic

[goxu1]

Anyone know what the length of the caliper pin should be for the xu1?
I bought a set off eBay and they seem to short.
The hole for the clip is hard up against the caliper making the clip impossible to engage

[S pack]

The LJ parts catalogues list the same brake pad retaining pin and clip for all 6cyl calipers.

[claysummers]

Would have to be quite a bit longer than standard with the spacer and thicker disc?


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[Dr Terry]

It might be from an HD/HR or Cortina, which are similar but slightly shorter.

 

AFAIK all LC/J (6-cyl) & all HK/T/G calipers use the same length pin, p/no. VS10759.

 

Dr Terry

[Bazza]

goxu1

 

The pins go from the inside to the outside on the Girlock calipers.

 

Bazza

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[goxu1]

just going off this pic from stevemc32's build I can see there is plenty of pin hanging out to get the clip on.

But the ones I bought off ebay only hang out about 5mm and theres not enough room to get the clip on due to the shape of the casting.

So I was curious to know the length of the pin from the underside of the head to the end....

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•  xu1 caliper.JPG   126.02K   5 downloads

[Dr Terry]

Those pins aren't the same as the originals.

 

Look at the pic & the R-clips go thru the pin much closer to its head, so the caliper casting shape will have no effect.

 

Try to find some closer to the originals.

 

Dr Terry

[S pack]

The original brake pad retaining pins are 65.5mm long from the underside of the mushroom head.

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[claysummers]

Same as HR


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[S pack]

Almost the same. The LC/LJ pins are a few mm longer.

[claysummers]

My short term memory failed me Dave. I thought you had said 64mm. So HR are 1/8” shorter. Did all the LC LJ sixes have the 5/8” discs then? I thought it was only GTR, XU-1 and KTG v8.


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[S pack]

Hi Clay, only the XU1 had the thicker 15.6mm rotors. The GTR and the J52 optioned S & SL had the 12.7mm rotors.

I believe the HR rotors were 9.7mm thick.

[claysummers]

Thanks Dave. I had the original rotors on my HR brakes for years. They were a composite and 10mm sounds right from memory. The outer layers were nearly worn through when I replaced them with a one piece disc which seemed thicker, but of course it would being new.


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[S pack]

Genuine HR rotors were not a composite construction, they were a one piece casting, however they were separate to the wheel hub.

[claysummers]

Yes separate to hub, but I am fairly sure these were original, and were certainly well worn in 1986 when I got them. They had a steel laminate on the braking surface, over cast main body.


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[Dr Terry]

Yes separate to hub, but I am fairly sure these were original, and were certainly well worn in 1986 when I got them. They had a steel laminate on the braking surface, over cast main body.


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I don't think that was the case. My memory of all original HD/HR, LC/LJ & HK/T/G rotors were that they were cast iron, with a steel ring at the outer edge to reduced harmonic noise. They look to be laminated, but are not.

 

All of the aftermarket replacements were just cast iron, with square edge & no steel ring.

 

Dr Terry

[Dr Terry]

My short term memory failed me Dave. I thought you had said 64mm. So HR are 1/8” shorter. Did all the LC LJ sixes have the 5/8” discs then? I thought it was only GTR, XU-1 and KTG v8.


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Yes, the XU1s had a 5/8" thick rotor, all other disc braked LC/LJ (6-cyl) had 1/2" thick rotors.

 

The HK/HT/HG disc rotor thing is more complicated. All HK had 1/2" rotors, all HT also had 1/2" rotors except for the Monaro GTS350. Then all HG (6 or V8) got 5/8" rotors.

 

HD/HR got 3/8" rotors & shorter pins.

 

Dr Terry

[claysummers]

Thank you good doctor. Can you comment on the HD HR rotor composition? I distinctly recall the cast rotors having a steel surface laminated on the friction area.


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It did appear that way. It looked to have 2 thin layers either side of a steel spacer, but it wasn't quite like that.

 

As I said, it was basically a cast iron disc with a steel ring at its outer edge.

 

Dr Terry

[S pack]

Dr T is correct. The OEM rotor was solid cast iron with a groove machined in the periphery of the rotor and a steel ring installed in the groove.

Edited by S pack, 10 February 2022 - 12:21 PM.

[claysummers]

Missed your first comment Dr T. Yes it appeared to be a laminate but it wasn’t. I remember being concerned that the “laminate” was going to either wear through or delaminate and seize. Thanks for the clarification guys.


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[Dr Terry]

What used to happen in extreme wear situations, was that the cast iron wore so thin that the outer ring came loose & got mangled between the wheel & the caliper.

 

Dr Terry

[claysummers]

Yes I would say that is what was imminent with mine in hindsight thanks Terry and Dave.

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[claysummers]

I got hold of a set of HR discs, calipers, hubs and stubs recently. Thanks to Bruiser for backing plates as well. The calipers are minus pins so will have to source some, along with pistons and rotors.

Here is a picture of the original rotor showing the harmonic balancer ring. These are close enough to end of life. Looks like the ring was tack welded here. I guess they would have been like a big snap ring.

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