rear mounted rack on hr front xmember.

dave68 · Post by **dave68** » Fri Dec 05, 2008 4:05 pm

Hi all, I am in the middle of a rear rack mod to a hr xmember. I have it all welded up and have the hr stubs bolted up. I have turned the steering arms over for the rear mount rack and now I am unable to fit the hr caliper as the steering arms sit over the rear capiler bolt hole. My question is what steering arms do people use with the standard hr stubs for a rear rack mount?
Help please.
Thanks.

NoMAD · Post by **NoMAD** » Fri Dec 05, 2008 4:10 pm

Not sure on the HR Stubs side of things, but an option is speak to whoever did your Rack (unless you did....

)

I've used the VC Commo Rear Rack and using HQ stubs/Arms for that lowering effect and HX Callipers and everything Bolts up goes form Lock to Lock without a problem...(however this is only manually as i havent driven it....

Cheers
NoMAD

FB MAD · Post by **FB MAD** » Fri Dec 05, 2008 4:33 pm

Not familiar with rear mount rack conversions but have you tried swapping the stub axles over ( ie left to right ) and fit the caliper to the rear??

Just a thought,

The instructions I've got for front mount rack ( CRS ) say that the HR arms have been "reset " for front rack fitment but not too sure whether same would apply for rear mount rack.

FB MAD · Post by **FB MAD** » Fri Dec 05, 2008 4:41 pm

Dunno if this helps but just had a look on the Rods Racks site and he mentions for his rear mount racks to use a HQ steering arm,short one about 100 mm from tie rod bolt hole on the arm to the first bolt hole that bolts the arm to the stub.

Read somewhere else ( another forum ) that the arm that is needed is HQ drum brake arm??

FCOV6 · Post by **FCOV6** » Fri Dec 05, 2008 4:54 pm

FB MAD wrote:Dunno if this helps but just had a look on the Rods Racks site and he mentions for his rear mount racks to use a HQ steering arm,short one about 100 mm from tie rod bolt hole on the arm to the first bolt hole that bolts the arm to the stub.

Read somewhere else ( another forum ) that the arm that is needed is HQ drum brake arm??

The short arms are from HQ-WB's with PS and they are hard to find and $$$

dave68 · Post by **dave68** » Fri Dec 05, 2008 10:45 pm

Thanks Terry, yer that was the problem, swapped them and off we go. The rack kit came from Pat Gardner and it looks ok. I have the red in, now all I have to do is get the steering column right and redo the DS engien mount as it is too short by 10 mm.This lets the steering rod hit the oil filter, so the xmember is out again for the mod.
Have run out of time so the ute stays here and I am back ina couple of weeks to finish it off, the joys of mods. Thanks again guys.

Sammy · Post by **Sammy** » Mon Dec 08, 2008 2:16 pm

i've got the same rack in my car and im using the hr arms at the moment ... i don't have any problems with brakes because i can using a hoppers stoppers kit ... but i am interested to know what the end qresult was ... hq short arms ?

does this screw around with the steering geometry when corning or what ?

dave68 · Post by **dave68** » Tue Dec 09, 2008 5:56 pm

Hey Sammy, got lucky scored HQ stubbs, rotors, calipers and steering arms for nothing. Bolted them but haven't driven it yet as I have a few other little issues to deal with. Because the rack is VB I need different tie rod ends so I am sourcing them at the moment. So when I drive it I will report in. Won't be for a couple of week .

FATBOY · Post by **FATBOY** » Sat Jan 17, 2009 10:00 pm

Update needed

regards fatboy

dave68 · Post by **dave68** » Tue Jan 20, 2009 3:43 pm

Update as requested..... Well after a lot of f@#$%^g around and removing the Xmember 5 times and cutting the brackets off X2 we got it in. I am unable to use the Hq calipers as I loose too much steering because the line are too close to the Xmember, will have to do some more research into that problem. The turning is verry good no undue vibration at speed( I haven't gone over 80 as yet) and it is so much better to drive. When I get back to Syd I will put up some picks....

Sammy · Post by **Sammy** » Wed Jan 21, 2009 2:15 pm

there are a few different types of calipers out there, one of them has the lines coming out of the inside of the caliper and pointing straight at the centre of the stub axle this is probably the one you need ?

oldnek · Post by **oldnek** » Thu Jan 22, 2009 10:40 pm

Hi Guys" Here is the experience's that I'm aware of,
Firstly correct steering geometry, will be affected regardless of which stub and steering arm combo you will run. Any rack fitted to the HR front end will be terrible in a real world, but an improvement to the modifiers world, over standard and the reason is this.

The bow or bend in the front crossmember is to excessive for any good rack fitment, especially if mounted at the front, thats why you have poor lock and excessive toe change left to right, ackerman is not good when turning, which affects lock turns and mild cornering at speed.

"That why nearly all vehicles fitted with Rack and Pinion steering have straight crossmembers."

However! The rear mounted rack is better suited for the mod, over the front mount and eliminates a lot of the front mounted downfalls.
But with either mod in a front or rear rack fitment, the correct steering arms should be employed. You should not fit rear mounted steering arms on a front mounted rack or vise versa.
CRS made modified steering arms to suit front mounted racks and these are re-bent to be closer to the wheel when looking from the front. Ever noticed how far out the tie rod end on the steering arm projects on the standard steering assembly on a Holden with rearward steering compared to a front mount steering set-up, were the steering arms are closer to the disc rotor..

Designers have Ackerman incorporated in the steering geometry to promote (in a simplified way) better turning circle with less scrub and drag, causing less tyre wear.

As FCOV6 mentioned, Holden fitted shorter steering arms to there Power steer Models, They did this to stop light high speed steering feel, and to make it more efficient at low speeds.

A quick check to see if your on the ball park, is draw a imaginary line though the top and lower ball joint. Then from this point draw another line from there to the centre of the rear diff. Do that with the other side So basically you have a imaginary triangle, layed out under your car
Front mounted racks should have steering arm-tie rod point follow the side of the imaginary line, whilst rear mounted racks should follow the inside.

I hope I haven't confused the issue.

Regards John

Trev · Post by **Trev** » Fri Jan 23, 2009 4:05 am

It even makes sense to me, nice one John, Trev

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