Rear brake upgrade thoughts - 80 / 105 / 100 series

[hdj105]

Has anyone ever considered fitting the 47/60/75 series type front 4 piston calipers to the rear of a 80 / 105 or 100 for better braking?

My 105 is fairly heavy and I'm considering going to 35's, but still want to maintain excellent brakes. I think due to the constant extra rear weight (LR tank, rear bar, wheel carrier, drawers, etc) that upgrading the rear brakes may be a good idea.

Late 80's and 105's have 335 x 18mm rear discs, the 60/75's had 305 x 20mm front discs. Providing it was possible to mount them can anyone see any problems?

ABS should be able to take care of any slight proportioning miss-match if required, and I *think* some Hilux calipers may also offer alternative pistion sizes should smaller ones be required.

[manitou]

You will need a handbrake included in this conversion won't you?

[hdj105]

You will need a handbrake included in this conversion won't you?

No mate, handbrake (drum) is located inside the rear disc, totally independent to the caliper.


Anyone else have any thoughts?

[treebruiser]

Dont quote me on this but I have read/heard somewhere that the early (92/94) 4 runner twin pot callipers will bolt on. I'll see if I can find it somewhere.

[hdj105]

Dont quote me on this but I have read/heard somewhere that the early (92/94) 4 runner twin pot callipers will bolt on. I'll see if I can find it somewhere.

Thanks Treebruiser, any info would be great.

I should have stated the original calipers are standard single piston sliding units.

[manitou]

I just reread the post. You are only changing the calipers. Make sure you check out the size of the pads. Make sure they are a close match for the height of the contact area other wise you can and up doing alot of work for not much improvement. Another problem to look out for is if the piston size is much bigger than standard it will affect your pedal travel.

[hdj105]

I just reread the post. You are only changing the calipers. Make sure you check out the size of the pads. Make sure they are a close match for the height of the contact area other wise you can and up doing alot of work for not much improvement. Another problem to look out for is if the piston size is much bigger than standard it will affect your pedal travel.

I think I have some 60 pads, so I'll check the contact area - now that you mention it I'm sure the current rears will have a much smaller swept area.

I don't *think* the pedal travel will be an issue, as the way the ABS system works the rear brakes seem to be fed constant pressure and flow by the master. A better way to explain it is if I crack a rear nipple to bleed the brakes, all I need is the key on and pedal depressed and it will keep pumping fluid until the reservoirs empty.

[dow50r]

Gday Greg
early 60/40 has two 22mm and two 35mm pistons...one each side of calliper, later (90 plus lux and hzl75) has 4x35mm, 4runner v6 has 4x45mm, same as all 80 fronts.
My first thought was to the late alloysupra rear calliper or similar with twin pistons opposed to the std single piston. 300zx/skyline are another source...the rx7 front calliper has 4x22mm pistons, is alloy and large space feet....as you know im also chasing better brakes, and have gone 100 5 stud to get 100 callipers on 100 discs up front....also another thing to discover is will the supra calliper body fit in the cruiser holder...i will go out and checkl a cressida calliper against a 100 calliper now

[dow50r]

well Greg.....ive put a std front calliper from a cressida next to the 105 rear and the body will bolt straight on...or so it looks....piston size is 50% larger, meaning double the clamp force....std cressida front disc thickness is 20mm, might need 17 inch IFS rims and 56mm snake racing spacers...but i reckon it will work with std rear pads

[hdj105]

well Greg.....ive put a std front calliper from a cressida next to the 105 rear and the body will bolt straight on...or so it looks....piston size is 50% larger, meaning double the clamp force....std cressida front disc thickness is 20mm, might need 17 inch IFS rims and 56mm snake racing spacers...but i reckon it will work with std rear pads

Andrew, are you saying the whole Cressida caliper will bolt on, i.e. the axle mount holes are the same, or do you mean the caliper unit (alloy bit) will fit onto the OE 80/105 sliding pins?

Is the Cressida caliper still a single piston sliding unit, with a 50% larger piston than the 80 / 105?

[Ice]

bit of a dig, but on fitting to an 80/75

the mx83 calliper (pistion assembly) fits in the 80/75 series frame

piston diamter is 60mm opposed to the 45mm standard 80

the frame requires some clearancing, the mx83 pads also need some grinding

you will get slightly taller swept area with the mx83 pads, it about 5mm downwards.. compared to 80/75 series standard pads

increased pedal travel is not an issue for me as ill be adding a hydroboost system down the track

this is for my comp truck not a road car...

[oldmate]

I would look at making sure the rear lspv valve (if the 105 has one) is adjusted properly, and that proper pressure is being applied to the rear brakes.

I don't think you want to go upgrading the brakes. The rears are smaller and have less force for a reason. Make them to powerful and the rear will lock under heavy braking before the front, and that will cause the rear end to step out, which could be disastrous if you are on a bend, or have a trailer on.

Fully loaded the average 100/105 weights over 3 tonne. I think it's just a matter of accepting that it is twice as heavy as an ordinary car, and is much taller (higher centre of gravity) and thus handling and braking will never be car like.