Harrison brake bias - balance bar?

[Ryder]

Just wondering if anyone has attempted to address the Harrison brake bias issues by using a twin master cylinder balance bar setup? And if they have come across or could think of any compliance issues?

Cheers

[Krait]

Originally Posted by Ryder

Just wondering if anyone has attempted to address the Harrison brake bias issues by using a twin master cylinder balance bar setup? And if they have come across or could think of any compliance issues?

Cheers

Balance bars are legal, but cannot be adjustable. Once the balance is set to the satisfaction of your engineer the bar must be locked in place permanently, usually by a welding tack.

[Ryder]

Thank you for the info

I'll clear it with the engineer, then I reckon it'll be a very good way of permanently fixing the issue. Plus, from what I understand, it would mean I wouldn't need a brake booster anymore either - might help clean it all up a bit.

[Zedn]

You won't need a booster if you size diameter of cylinder and pedal length correctly. You can also go the reverse mount master cylinder and then you will only have the reservoir on the fire wall. I started out doing this, but then decided to change to the road more travelled to minimise compliance risk.

[sambo]

Ryder is the purpose of the balance bar to restrict the Commodore front brakes so they're better matched to the Skyline rears? If so, you maybe left with few options for brake upgrades, since the rear brakes are the limiting factor. Or maybe I don't fully understand how the balance bar works?

[muzzza]

Ryder,
Would suggest that unless you change to more appropriate calipers, a bias bar set-up, without a booster in a road car would be a backward step. You lose the safety requirements of a dual line system and also considerable pedal power without the booster. The booster enables a far greater displacement of fluid,
that sliding calipers - typically GM / Holden depend on to operate effectively.
If better brake balance is what you are after, you may be better ensuring you have compatible calipers front and rear, with the correct master cylinder bias. There are some good caliper options in earlier Harrison brake threads. Murray

[Ryder]

My understanding of the R33 brakes Vs the VT brakes is that the VT ones are not too much for the R33 ones, but the bias is just off. So, using a balance bar (as I understand it) would essentially mean that the rears come on stronger, and would not affect the stopping power of the fronts at all.

This site seems to explain it ok Performance Friction Brakes

I'm thinking this may be a better way to go for my needs, as I don't require massive racing brakes - just a safe and reliable way to stop lol

:Edit - I think I may need to have a chat to a brakes specialist. Have spoken briefly to one brakes supplier for hotrods, who seems to think the calipers should work together ok if set up right. But as he said, he's hasn't seen the car or looked into it much.

[sambo]

Race Brakes here in Melb commented to me that VZ front brakes were too big for R33 rears in a car with near 50:50 balance like a Cobra. I fitted their recommended Camira front brakes to the rear and problem solved. There's a bit of work machining the rear carriers to suit but it does fix the balance issue. Go with a proven fix rather than reinventing the wheel, as Muzza said.

Muzza is that your Harrison on carsales?

[Krait]

My Harrison has AP calipers all round, no balance bar required. Uses standard master cylinder and booster. Engineer commented it was one of the best stopping vehicles he'd tested.

I'm not saying that AP's are the answer just that properly sized disc/caliper combinations are necessary as a basis for safe performance.

I had a short conversation recently at LCS with a guy who wanted to adjust the brake bias on the right front only because it kept locking first. I strongly suggested that he get somebody knowledgeable to look at the suspension and corner weighting as what he was suggesting was dangerous.

My Cobra is also slightly bum heavy as the LS2 is lighter than a Ford donk.

[muzzza]

Sambo.........Yes. Not desperate to sell, but have some other projects in mind. Have built a lot of cars over many years and are gettin' the itch again ! Must be Crazy ( onset of old age and senility !! ) Murray

[sambo]

Good luck with the sale Muzza. Another Cobra?

Geoff, how are the AP calipers fitted to the rear? The brake guy told me the Nissan design uses a weird offset making it difficult to fit aftermarket gear.

[Krait]

Originally Posted by sambo

Good luck with the sale Muzza. Another Cobra?

Geoff, how are the AP calipers fitted to the rear? The brake guy told me the Nissan design uses a weird offset making it difficult to fit aftermarket gear.

Sambo, my Harrison has billet aluminium rear uprights using Commodore hubs/axles/diff.

I wonder what big braked R series Nissans use for calipers. We ran Sumitomos on my works replica Stanza years ago (built it 30 years ago and it's still competing in Victoria).

[sambo]

Yeah OK that makes it a little easier Geoff.

There are a few aftermarket R33 big brake kits on eBay from D2 and Ksport, running 2, 4, 6 or 8 piston calipers and right up to 400mm. Pretty bonkers for rear brakes!

My engineer wasn't too keen on going down that path. ie, questions about quality and safety.

Edit: plenty of Brembo kits from international sellers too. Maybe that's an avenue, being an established brand? $5k delivered, ouch

[Krait]

Originally Posted by sambo

Yeah OK that makes it a little easier Geoff.

There are a few aftermarket R33 big brake kits on eBay from D2 and Ksport, running 2, 4, 6 or 8 piston calipers and right up to 400mm. Pretty bonkers for rear brakes!

My engineer wasn't too keen on going down that path. ie, questions about quality and safety.

Edit: plenty of Brembo kits from international sellers too. Maybe that's an avenue, being an established brand? $5k delivered, ouch

You know you want 20" wheels. Don't Subi's use Brembo? Calipers are easy, it's getting the disc offset that's the pain. Those dogbones in the picture are similar to mine. Was your engineer specific in his concerns? Every man and his dog seems to make/rebadge calipers these days.

[sambo]

Yeah, and a fooly sik woofer to go with the 20s. That's how I roll.

Two words I seem to recall at the time were "China" and "crap".

Originally Posted by Krait

You know you want 20" wheels. Don't Subi's use Brembo? Calipers are easy, it's getting the disc offset that's the pain. Those dogbones in the picture are similar to mine. Was your engineer specific in his concerns? Every man and his dog seems to make/rebadge calipers these days.

[Krait]

Originally Posted by sambo

Yeah, and a fooly sik woofer to go with the 20s. That's how I roll.

Two words I seem to recall at the time were "China" and "crap".

What about Hi Spec?, Aussie Mike uses them and hasn't posted any negative feedback that I've seen. Looking at their website they do play with Nissans so might have some insight into the rears. I know you'll miss the 20's but time will ease the pain

[07cob]

Originally Posted by sambo

I fitted their recommended Camira front brakes to the rear and problem solved.

Sambo

I, for one, would be very interested in the details of this upgrade. My brakes are good but I feel that they could be better. I like the idea of increasing the rear braking capacity. Any photos or stories would be appreciated. Maybe on another thread to avoid the hijack.

Cheers

Geof

[sambo]

Hey Geof, see the thread below for photos and other details.

Harrison brake bias - solved!

I still have my original uprights somewhere if you're interested in doing a changeover.