Brake upgrades, inc handbrake concerns

richiep

Club Member
As Gary notes, it’s geometry to a degree - making a handbrake cable and mechanism designed for drums work with the calipers. The caliper is in a different position to where the cable would attach to the drum, leading to slack and a nasty angle usually. A common hack (as on my red Z) is to cross the cable - right to left and vice-versa; that removes the slack and improves the angle to the calipers.

However, adjustability in the system due to the design of the existing mechanism is a limiting factor. One further hack is to make an extension for the arm attached to the handbrake lever, creating greater leverage on the adjustable rod in the trans tunnel. Also, adding more thread to that rod. I’ve done both on my car. Still, it’s limited in effectiveness and hence my interest in alternatives to the usual calipers and the idea of separate handbrake calipers as per Wilwood.
 

uk66fastback

Club Member
The rear Wilwoods on my old Mustang had an internal handbrake. I then changed the umbrella-under-the-dash handle for a tunnel mounted one. Worked pretty well.

The car didn't even need rear discs though, but they looked good ...
 

johnymd

Club Member
My issue is with the fronts locking up way to easy and I'm suspecting (due to the amount of dive) that the rear are not doing enough braking. Hence, I'm looking at changing the rears to disks. Plus the maintenance is way simpler.
 

IbanezDan51

Well-Known Forum User
My issue is with the fronts locking up way to easy and I'm suspecting (due to the amount of dive) that the rear are not doing enough braking. Hence, I'm looking at changing the rears to disks. Plus the maintenance is way simpler.

Hence a remote brake bias/balance adjuster is a great idea, you mentioned no bias above. They can really help get things set up perfectly
 

jonbills

Membership Secretary
Site Administrator
My issue is with the fronts locking up way to easy and I'm suspecting (due to the amount of dive) that the rear are not doing enough braking. Hence, I'm looking at changing the rears to disks. Plus the maintenance is way simpler.
My understanding is that drums are more efficient than disks, except they overheat quicker. so if the lockup/dive issues are present when the brakes are cool, disks won't fix it.
?
 

johnymd

Club Member
From what I understand, most brake bias valves are installed in the rears to stop the backs locking up. Would you suggest putting a variable cut off rate valve in the feed to the fronts?
 

IbanezDan51

Well-Known Forum User
From what I understand, most brake bias valves are installed in the rears to stop the backs locking up. Would you suggest putting a variable cut off rate valve in the feed to the fronts?
Front to rear bias is all you want to alter, full pressure to the fronts so no adjustability, wind the rear pressure bias up until its even or how you want it to work... If tracking the car you might want the rears to lock up sooner or vice a versa. Depends on the corners and how you position the weight of your car to go around them. Pro-karts lock the rear brakes up loads sooner than the fronts will ever but that's because they have more weight over the rear of the karts. Great fun for cornering :D
 

Turn & Burn

Club Member
Hence a remote brake bias/balance adjuster is a great idea, you mentioned no bias above. They can really help get things set up perfectly

You can’t easily reduce over powered front brakes, as far as I can research the bias valve can only be used to down rate an over powered rear. I think the bias valves further reduce power the harder you press the pedal so u could find yourself with minimal front brakes.
 

johnymd

Club Member
All the bias valves I have seen allow you to change the rate of pressure increase from a point that you set. The purpose of this is to delay the point at which the rears lock by reducing the rate of pressure rise. They do not allow you to apply more pressure than the master cylinder provides, only reduce the rate of rise in pressure.

It may be fine for go karts but you really don't want the rears locking up as you approach the apex of a corner. That will only end badly. Unless you are a drifter that is.

I think I need to increase the braking force to the rears and then use a bias valve to reduce the rear braking.
 

IbanezDan51

Well-Known Forum User
All the bias valves I have seen allow you to change the rate of pressure increase from a point that you set. The purpose of this is to delay the point at which the rears lock by reducing the rate of pressure rise. They do not allow you to apply more pressure than the master cylinder provides, only reduce the rate of rise in pressure.

It may be fine for go karts but you really don't want the rears locking up as you approach the apex of a corner. That will only end badly. Unless you are a drifter that is.

I think I need to increase the braking force to the rears and then use a bias valve to reduce the rear braking.

Yes sorry Johny, that's correct. You don't alter the pressure, its only an inline restrictor but you wind it up to a point that works with your brake set up. Theres a limit, like you say, contact area of the pads and disks/drums etc plays a part on equalling the braking force out, as do your contact patch of your tires. You need to set up a brake bias up with an adjuster ideally for road use under maximum braking force to ensure the fronts always lock up first, unless you want some hairy moments.

Sometimes locking the rears up on an apex could be useful...

Would be good to have variable brake bias depending on speed and braking force, monitoring your corner weights etc Lets throw a yaw sensor in for good will and build up a decent esp system.
 

datsfun

Club Member
For those not aspiring to bigger brake conversions, what brake parts are recommended for stock sumitomo calipers for normal driving ?
 

red baron

Well-Known Forum User
your lucky day rich have a brand new rear brake conversion for sale disc calipers brackets hoses and bolts other parts as well am going to put on ebay give you first chance
 

Woody928

Events Officer
Staff member
Club Member
I've only heard good things about these Project Mu pads

https://revmatch.net/product/project-mu-type-hc-plus-brake-pad-datsun-z-69-78/

I'm sure EBC do sets to ?

Never used them but heard very good things about Project Mu. Porterfield R4S are very good, carbotech makes fantastic pads but are very dusty.

For general road use you can use far more generic pads though, that said I'd stick clear of EBC. The quality is notirously poor and I've know of several failures through spirited use and trackdays....
 
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