18 replies to this topic

[BIG KEV]

When doing the HQ brake upgrade on a LH/LX Torana is there one caliper from the hq-wb cars that is preferred that is better or easier to fit 

I already have HQ stubs and rotors

A pic of caliper that is recommended would be appreciated 

 

Thanks Kevin 

[yel327]

The easiest is a UC PBR caliper with Torana brake pad holder. Straight bolt one and easy to find. These ones:

 

https://www.ebay.com...ERoCv6gQAvD_BwE

 

You can see they have top entry brake hose and one of the slides on each one uses an Allen headed bolt, so it clears the Torana tie rod end. See the cast iron bit that says TORANA? You replace that with ones that say HOLDEN.

 

BUT, some people hate the calipers. I never had a drama with them, but others hate them. Here is a pair of HX ones, see they are HOLDEN not TORANA, and no top entry for hoses. Also see both slides are the same, use normal bolts not one recessed.

 

https://www.ebay.com...:Bk9SR5Dz_JKSZA

 

The next easiest is HQ PBR. This is what was on L34, but on L34 they put blanking plugs in the bottom hose holes and added hose entries into the top. See images of my old L34 calipers that I was going to use on my HK but changed to a Rodtech front end:

 

 L34 caliper 1.JPG   88.09K   4 downloads

 L34 caliper 2.JPG   85.16K   6 downloads

 L34 caliper 3.JPG   97.4K   4 downloads

 L34 caliper 4.JPG   95.26K   3 downloads

 

Probably the best caliper and the one with the biggest pad area is the HZ-WB Girlock, these were modified for use on A9X. Fair bit of machining on them to clear the Torana tie rods. These:

 

https://www.ebay.com...:Bk9SR9LM7ZKSZA

 

 

 

[BIG KEV]

So would you recommend the PBR ones as i think i can get some of those ones 

or pay extra for the WB Girlock type not really keen on grinding the caliper 

[yel327]

I'd use the UC PBR ones, but word of warning - sometimes they are buggered from alloy corrosion. And you have to buy 4 x calipers to get all the parts (2 x UC, 2 x HX). I tried the HQ PBR ones on my LX but never liked the hose hanging downwards as it was damn close to moving stuff, and will be why GMH modified them for Torana.

[76lxhatch]

I've seen the HZ and WB ones weakened too, they look fine but flex under braking and all you get is a mushy pedal and a bit of heat. Not a bad caliper in general but they are getting a bit long in the tooth these days and the alloy ones don't last as long. Count me as another that doesn't like the HZ/UC caliper, they have more issues with flex and the slides never seem to work right.

 

They're a bit of a lump but my pick would be the HQ ones pictured above. Not much can go wrong other than sticky slides which is easy enough to fix. If the hose angle doesn't work for you they probably need replacing anyway and a brake place should be able to set up a fitting that changes the angle.

[axistr]

So would you recommend the PBR ones as i think i can get some of those ones 

or pay extra for the WB Girlock type not really keen on grinding the caliper 

 

Kev if you really want to go down the road of UC calipers I have a couple in the shed which were reconditioned before fitting to my hatch, however I only removed them to upgrade to 298mm brakes.

[yel327]

I saw some of the pad carriers off a HX on Gumtree or Foolbook last night. When I originally went down that path the intention was to find some A9X calipers eventually (remember this was the late 80's into early 90's and stuff like that was still around and easily found). I'd already put A9X axles and brakes onto a shortened HZ Salisbury and made an A9X front crossmember setup out of a mix of LX and UC stuff. So just experimented and made up the set of UC/HX calipers and the whole lot worked perfectly well. I never had any issues with the calipers. It had a HT-HG booster modified with Torana rear rod and was a straight PBR disc/drum alloy cylinder with the rear check valve removed. It wasn't a track car though, just a nice street car that got used for a few laps at Amaroo Park. It never ran out of brakes though, it ran out of tyres on the track way before brakes. Teh calipers were full rebuilds though with new pistons, genuine seals/rubbers and I was using Dupont silicone brake fluid back then.

[BIG KEV]

Kev if you really want to go down the road of UC calipers I have a couple in the shed which were reconditioned before fitting to my hatch, however I only removed them to upgrade to 298mm brakes.

Thanks for the offer Lenny but i am wanting to go down the path of the HQ calipers as i have most of the stuff here already including the Harrop arms 

[axistr]

Thanks for the offer Lenny but i am wanting to go down the path of the HQ calipers as i have most of the stuff here already including the Harrop arms 

 

I had them over HQ rotors.

[yel327]

As Lenny says, it won't make much of any difference with HK-WB stubs and HQ-WB rotors which caliper you use for clearance to everything if using UC, A9X or the Harrop steering arms. Other than the bottom hoses with all of the Holden calipers getting awful close to stuff, the HZ-WB Girlock caliper requiring machining of the cast iron carrier and the HX PBR style calipers lower attachment bolts fouling the tie rods. If Lenny sells them to you cheap enough, I'd run them and get the car sorted, then change to whatever you choose afterwards if you don't like them. You just have to make sure that you use the right pad carriers (with HOLDEN on them). You have to use the UC Allen headed bolts though for the lower bolts.

Edited by yel327, 10 July 2024 - 08:25 AM.

[gtrboyy]

Does Harrop still sell A9X steering arms?

 

Not seen them advertised

[RoyalPlum76SS]

Does Harrop still sell A9X steering arms?
 
Not seen them advertised

Yes, they are a bit over $500/pr now.

[RoyalPlum76SS]

There are 2 all cast calipers that came on HQ-HJ that would be suitable and wouldn't need modding like the HZ ones do.
The first are like Yel posted pics of. His are L34 but they were based off early HQ 'small pin'.
The next was known as 'big pin' and came off the later HQ and also HJ.
Either one of those are a reasonable caliper for street usage.

One also not mentioned is the all cast Girlock calipers which were fitted to some HJ and HX's (I believe) which are a good solid caliper. To use these you would need to slightly grind a bit off the bottom of the caliper bracket to give relief from the tie rod end but it would only be a very minor amount and it's a very thick bracket.

HZ are a fairly good caliper but as you know need the most amount of grinding. Do not use the WB version of this caliper as the banjo fitting on the back of the piston will foul on the Kframe on full lock.
I've mocked up a few calipers on a HZ stub with a Harrop arm with a tie rod end fitted so you can see the different types and their room, or lack there of, for the tie rod ends (cldnt fit t.r.e to the HZ caliper as its not ground)

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[RoyalPlum76SS]

Continued with more pics..

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[RoyalPlum76SS]

Just a pic of the difference between HZ and WB calipers noting the banjo fitting on the back of the WB's.

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[yel327]

There is a pair of the HX PBR on Foolbook near me if you go down that path. They are showing in Wakefield NSW. If you buy them and need them picked up let me know.

[AbsynthHatch]

Where does the HZ caliper needing grinding to allow relief for the Tie Rod end?
On the alloy or cast iron part of the caliper?

[RoyalPlum76SS]

Where does the HZ caliper needing grinding to allow relief for the Tie Rod end?
On the alloy or cast iron part of the caliper?

The cast iron cradle part needs a bit of a scallop out.

It should end up looking something like this when finished.

Attached Files

•  0000000000000000000000000000000000000pp.jpg   34.56K   8 downloads

[AbsynthHatch]

Thanks for the image.

Was this something the brake manufacturer did solely for the A9X or was it competed by someone else for Holden?