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A9X brake info


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#1 toranamech

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Posted 31 July 2007 - 01:38 PM

I have read through quite a few threads here and would like to know about the front and rear caliper types used on A9X torana as I plan on making a replica one as I haven't won lotto lately and don't have a lazy 100k lying around.

The rear brakes, I have a UC sle disk brake rear and a HZ 10bolt Salisbury rear diff. Logic would say to me the A9X diff was a shortened version of the HZ diff, given the era and the simple engineering of just shorter axles and housing tubes and mounts, is this the case? i.e handbrake cables, brake lines, mounting styles, bearings etc. are any of the UC parts apart from the mounts used?.

The front brakes, I have a set of HQ PBR's and a set of WB girlocks and some LX alloy ones and UC ones, what type did they run in A9X's. apologies for my ignorance but I only have ever had xu1's and L34's and don't have any LX parts books (yet )

#2 Dangerous

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Posted 31 July 2007 - 04:27 PM

A9Xs used an HX 10 bolt Salisbury diff centre with shorter axles and axle tubes, and the HX disc brake rear. The handbrake actuation was different to the HX though, with the cables feeding in from the front using a different mounting bracket. The A9X floorpan was altered to mate up with the different upper trailing arm geometry of the HX diff centre, so you'll either have to alter your floorpan (better outcome), or weld LX upper trailing arm mounts to the diff axle tubes.

Someone is selling repro A9X handbrake cables on Ebay, and from memory, the bracket for the cables is shown in a drawing either in the parts manual, or the Eric Blair XU-1/L34/A9X torana book, which is also for sale on Ebay.

The front setup was Girlock calipers with a different brake line entry point and bleed screw location. The cast iron bracket that the calipers slide on was modified to give clearance for the steering tie rod. Use HQ (or preferrably HX or HZ One Tonner) stub axles, HQ rotors, and Harrop sells repro A9X steering arms.

Brake booster and master cylinder - well, that's Datto's strawberry patch, but depending on how close a replica you want, you can use an early V8 Commodore booster and master cylinder, and fit metric thread ends on your brake lines, to suit the Commy master cylinder threads.

There's also a guy on Ebay selling very good repro front brake air ducts too.

Good luck with the replica :D

#3 dattoman

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Posted 31 July 2007 - 04:50 PM

These are images of genuine A9X parts
Master cylinder
Booster
Master and booster bolted together
Front caliper showing fluid inlet position and bleeder
Rear calipers

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If you send me enough money I can duplicate most of this for you
Except the front calipers
But since you didn't win lotto....................

Late LX-UC booster can be modified to take ADR style master with prop built in
Master I use is Foulcan XC/D/E as it has the 3 imperial thread outlet ports
Rear calipers as mentioned are very similar to HZ
Using the UC ones you already have will put you close but you'd need the HZ brackets to push the caliper up to suit the HZ disc. Torana was a smaller discontinued discs
Closest you will come to calipers on the front will be WB. They have the more favourable fluid inlet position.

Good luck
Enjoy the ride

#4 Dangerous

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Posted 31 July 2007 - 06:01 PM

Datto, are the rear handbrake cable brackets the same as on some other Holdens? Are they HX ones swapped around? Can't remember, it was a long time ago that I played with the rear brake setup.

#5 dattoman

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Posted 31 July 2007 - 09:37 PM

Torana
HX
WB
3 different calipers as far as where the inlets and bleeders are
Brackets are same on WB and Torana

A9X caliper is same as UC

#6 Dangerous

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Posted 31 July 2007 - 10:36 PM

Brackets are same on WB and Torana

Ah, so the A9X handbrake cable brackets are just the WB ones reversed side to side, and forward facing, yes?

#7 dattoman

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Posted 31 July 2007 - 11:01 PM

Can't confirm or deny
Would need to relook at both cars

#8 toranamech

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Posted 01 August 2007 - 12:19 PM

Wow, thanks heaps for that Info, I think between all that I'll be able to make up the setup, I have two very simmiliar looking master cylinders to that one, I think one has 1" and the other 15/16 cast into the alloy body, but same integral porportioning valve.
I never had any probs with brakes at all on a stock L34 setup, just metalking pads, so I was just going to get a set of DBA slotted rotors good pads and the caliper setup you suggested.

You mention A9X same as UC was that front calipers or rear?, I thought the UC SLE disk rear would have used smaller calipers, but if it is just the HX Bracket, which I'm guessing is the same as WB?, I've got it pretty easy then.

As for the other componentry, the missing link was alway the steering arms but harrop seems to have that sorted out, and the stubs axles , no probs was aware of torans KPI on one tonners from the L34 days, Thanks again, pictures speak a thousand words for me, If I was in WA I'd drop a carton down for your troubles.

#9 Dangerous

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Posted 01 August 2007 - 12:46 PM

As for the other componentry, the missing link was alway the steering arms but harrop seems to have that sorted out, and the stubs axles , no probs was aware of torans KPI on one tonners from the L34 days, Thanks again, pictures speak a thousand words for me, If I was in WA I'd drop a carton down for your troubles.

The Harrop arms are in the order of $300 a pair, I think. Stock UC ones are a reasonable compromise (at least better than LX ones) if you're looking to save some $$ here and there.

Harrop A9X spec steering arms

With the Girlock calipers, you might have a fouling issue on full lock with the rear of the upper wishbones. GMH just cut bits off the upper arms to provide clearance, and may have also added a larger steering stop on the front of the lower wishbone - the bit where the steering arm hits the wishbone on full lock to limit steering travel.

One thing I'm not clear on with the Harrop steering arms, and no-one here seems to have checked - or reported on, is that they don't have the same 'ear' on the tie rod locating area which limits steering lock - once again, the bit that hits the lower wishbone on full lock to limit steering travel. If the Harrop arms allow more steering lock, then this would increse the probability of the caliper bodies fouling on the upper wishbones.

Here's a pic of an LX (red), UC (black) and A9X (black with blue splash) steering arm in that order from top down. See how in this and the next pic, the UC arm drops lower than the LX one, and the A9X one drops lower again. The A9X one had to drop lower, not only to give more clearance for the tie rod end, but also to return the steering rack geometry to horizontal when using the HX stub axles.

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Note the steering stops on the left side of each arm

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These are the Harrop arms. See how they don't have any steering stops?

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Harrop arms would be the best to use if you can scrounge up $300, but I'd want to be checking the steering travel and making sure the calipers don't foul, or the rack gears don't run up to their limit. I've used UC arms, and it's a reasonable compromise.

#10 _rorym_

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Posted 01 August 2007 - 12:52 PM

Good info and pics D..I too am starting with the UC arms.
R

#11 ReplicarSLR

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Posted 01 August 2007 - 03:35 PM

Thanks guys some excellent info there, most helpful. I am going to do the same conversion too (brakes, stubs, steering arms etc ). I intend to use the Harrop arms but also have the same concerns regarding them not having the steering limiting "ears" cast near the ball joint connection. I assume that the only way around this is to fit steering limiting plates to the lower control arms that are suitably sized to limit the steering prior to the steering rack limit or the brake calipers hitting anything, similar to the ones on UC lower arms?

#12 toranamech

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Posted 02 August 2007 - 12:19 PM

Thats geat info and pictures, I rally appreciate your effort and explanation, it really cleared things up for me.
The L34's have a @40mm sqare block welded in and the upper control arm ground away for clearance issues, very rough but effective. As most people who hav had these cars will know, in some cases on full lock with suspension compressed, the caliper gets pushed away from the disk, bit of a fright, :blink: no brakes until you pump it again.
Does the A9X use the same rear rotors as the HZ/WB disk rears?

#13 Dangerous

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Posted 02 August 2007 - 12:31 PM

The L34's have a @40mm sqare block welded in and the upper control arm ground away for clearance issues, very rough but effective.

Does the A9X use the same rear rotors as the HZ/WB disk rears?

A9X has the blocks on the front crossmember too, and uses the HJ onwards rear rotors

And you're right about the no brakes issue - gets your attention quick smart! :blink: :huh:

#14 _rorym_

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Posted 02 August 2007 - 04:57 PM

Like Dangerous said..Arrimar and I ground out about 5-7mm on the inside of the top arm near the caliper knuckle for some clearence..same as GMH did..I would suggest you do the same.
R

#15 Dr Terry

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Posted 03 August 2007 - 09:38 AM

A9X has the blocks on the front crossmember too, and uses the HJ onwards rear rotors

Hi Guys.

HJ & HX do not have any rear rotors. The first production Holden to have rear discs was the A9X (in Sept '77). Then in Nov '77 when the HZ was released, they had rear discs standard for GTS & both Statesmans & optional on all other passenger cars with V8s.

So the HZ (& then the WB) actually used A9X discs, not the other way around.

Dr Terry.

#16 Dangerous

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Posted 03 August 2007 - 10:30 AM

Oops - my mistake. Thanks for the correction Doc T - I always thought that rear discs were an option on the last of the HJ Monaro Coupes, and also standard on the HX LE.

#17 REDA9X

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Posted 03 August 2007 - 12:55 PM

They were an option on HX I believe, and rear discs were an option on the entire LX range, though I have only ever seen one.

#18 dattoman

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Posted 03 August 2007 - 04:41 PM

There was a nice romour going around many years ago of some late 73 HQ's for NSW Police that had disc rear
6 cars
Not sure how true it is but the guy I heard it from was trying to get people to believe it so he could run disc rear in his Nc Monaro

#19 Litre8

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Posted 03 August 2007 - 05:29 PM

Rear disks an option on the LX range????

#20 toranamech

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Posted 03 August 2007 - 05:43 PM

I think I remember reading a mag of the era that said words to that effect about the A9X, the first holden with four wheel disks.
But I have seen those LE monaros with diskbrake rears, didn't know if they were factory because it was around 85 when I first bothered to check one out.
As for the disk rears in the LX's, I have seen a one owner 253 manual with air sl/r with a disk brake rear end, I though it was odd, but he ordered it like that, so it was available but expensive. I'd like to know where that car got too :rolleyes:
Once again thanks heaps for the info, I am following up a lead on a guy who lives local(less than a km away) who apparently still has his A9X he bought new in 77, I know hes got heaps of old cars restored, but I never talked about Toranas with him, I would be very surprised if there is still a "one owner, low kms, never touched" A9X about, but will keep you posted.
I

#21 Dr Terry

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Posted 04 August 2007 - 08:12 AM

They were an option on HX I believe, and rear discs were an option on the entire LX range, though I have only ever seen one.

Hi Guys.

There were no rear discs offered on late HX. There was however the so called Delco-Moraine anti-lock rear (drum) brake set-up offered as an option on cars with the 308 TH400 combination.

There were no rears disc ever offered on any cars with banjo diffs. This means all LX except A9X. Although with a few minor mods they will fit.

Rear discs were optional on all UCs, as these had small Salisbury diffs & the only UC to have them standard was the Sunbird SL/E. There were 2 variations in UC. Some had the hand brake cables pull from the front & others had the cable pull from the rear. This change took place when the Commodore style brakes were introduced into UC production in mid '79.

Dr Terry.

#22 REDA9X

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Posted 04 August 2007 - 02:49 PM

Terry, sorry to have to correct you, but rear discs were an option on LX with Banjo diff.

#23 enderwigginau

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Posted 04 August 2007 - 03:15 PM

Sorry Terry, but I have to back Mick up.

The rear discs were an option on the LX (identical to the UC bits, except pull from front with the HZ style brackets) but never appeared in a Parts Catalogue or Options Sheet. Mick if you have any paperwork that does refer to them, let me know.

I have always been led to believe that they were never fitted to a single car, but if Red has seen one then that is good enough for me.

This was one of the reasons it made it so simple for GMH to throw the discs onto the A9X, as they had already done the engineering.

Grant..

#24 _rorym_

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Posted 04 August 2007 - 05:55 PM

There was a nice romour going around many years ago of some late 73 HQ's for NSW Police that had disc rear
6 cars
Not sure how true it is but the guy I heard it from was trying to get people to believe it so he could run disc rear in his Nc Monaro

Gotta watch those racers...they will tell you anything to get parts under your nose.
R

#25 Litre8

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Posted 04 August 2007 - 06:17 PM

This was one of the reasons it made it so simple for GMH to throw the discs onto the A9X, as they had already done the engineering.


Except that the A9X had a different rear floor pan and different axle assembly.

I have never heard of any LX apart from the A9X having rear disks (option or otherwise). Back then we would have killed for rear disk brakes and many had to wait for the UC to install a set. My vote goes with the Doc.




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