C70 T5 brake options

[sumdarkplace]

Hi, first post

I'm looking for options for improving the brakes on my 2000 C70 T5. I have recent new pads and discs all round, and replaced the fluid with dot5.1 last week. The brakes were still not as good as they should be. Then I took a "spirited" drive over the moors from Burnley to Hebden Bridge of about 10 miles and the brakes faded appallingly!
I need to check, but I'm pretty certain I have the 302mm setup.

My thought was, do the 320mm setups from the later (p2) models fit? If not, how much work would it be? Are we talking custom caliper mounts?

The other idea I had was getting a pair of Nissan 4 pots from the 200sx, and making mounts for those. The standard setup for them is 280mm x 28/30mm but they would fit snugly around a 302mm disc. I figure if I would need to make custom mounts for the p2 stuff, might as well move up to 4 pots. Only issue I can foresee is that the standard master cylinder may not be wide enough to move enough fluid, and I will end up with horrid pedal travel again!

I'm on a pretty strict budget

Anybody have any thoughts?

[Biff]

I would of said you need to find the cause of the pedal failing first, are you sure they are bled properly & the seals in the calipers are ok? I had loads of problems with my brakes & ended up rebuilding every caliper on my v70r.
I had the 302 set up with genuine volvo discs & ferrodo ds500 pads. They were very impressive on the big estate so should be good for the c70.
Pads were dear but worth every penny & I'll be buying the same set up when my next car needs it.
The set ups your talking about will cost you more unless you want to change wheel size etc.

[sumdarkplace]

They were bled properly. I've just bought a second C70 to strip for parts, so I'm planning on stripping and rebuilding the calipers and MC, but I'm tempted to just skip straight to a brake upgrade.

The 200sx steel cast 4 pots go for around £100-150 a set, and they run a similar offset, so should sit nicely under the standard 17's. It also gives me access to a really good range of pad options. The ideal would be to find a decent set of 300ZX TT all alloy 4 pots. I just missed a set on ebay for £82!

Does anybody who's upgraded their calipers have any issue with pedal travel?
Is there a bigger MC option that is a relatively straight swap from another model?

Thanks

[stribo]

There are a few people running big brake set ups, as far as I know they haven't had to change the master cylinder.

[M-R-P]

As above - brembo 4-pots on 350mm disks aren't unheard of on these cars. Not cheap tho.

[sumdarkplace]

Thanks guys.

Going to do some more research.

Am I right in thinking the calipers are the same for all engine variants of the C70, it's just the carriers that are different?

[oblark]

280 mm discs dangerous
302 mm discs adequate
320 mm discs with 4 pot brembos is what 850's should have had fitted

[stribo]

Thanks guys.

Going to do some more research.

Am I right in thinking the calipers are the same for all engine variants of the C70, it's just the carriers that are different?

Yes, same calipers, different carriers.

[M-R-P]

280 mm discs dangerous
302 mm discs adequate
320 mm discs with 4 pot brembos is what 850's should have had fitted

...And a P2 with 336mm brakes is "superior" lol.

Awaiting backlash

[oblark]

...And a P2 with 336mm brakes is "superior" lol.

Awaiting backlash

You need bigger brakes on a P2 as it weighs a million tons

[stribo]

...And a P2 with 336mm brakes is "superior" lol.

Awaiting backlash

A single piston sliding caliper is not superior to a 4 pot caliper.

[M-R-P]

A single piston sliding caliper is not superior to a 4 pot caliper.

Don't knock it till you've tried it dude

[Ettienne]

the 336mm brake very well, but tend to suffer fade quicker, than the s60r , v70r 4 pots. As a budget brake they are very good.

There is a better range of pads and discs for the s60r's / v70r

The s60r / v70r discs are 4mm wider over the 336mm so helps with heat dispersal.

The extra 6mm of disc on the 336mm make no difference infact the 336mm by volume and weight are a lighter disc iirc.

Plus the pad area is bigger of the R models.

Braking obeys 3 main rules

clamping force.
leverage (disc size).
pad area.

I have run an s60r with both of these set ups and its only at repeated braking the differences show up a lot, but there is a smaller difference under normal braking.

[AshDVS]

I'd always found 850 and C70/S70/V70 standard brakes to be less than impressive too, but yours sound like they might be worst still.
Have you checked for any obvious leaks? Does the pedal get long after a 'spirited' drive?

What we often fail to think about is that some of these cars are nearing 20 years old (yours, as a 2000 model is 14 years old)! So, what are the lines like, what about the master cylinder and the booster?

[stribo]

the 336mm brake very well, but tend to suffer fade quicker, than the s60r , v70r 4 pots. As a budget brake they are very good.

There is a better range of pads and discs for the s60r's / v70r

The s60r / v70r discs are 4mm wider over the 336mm so helps with heat dispersal.

The extra 6mm of disc on the 336mm make no difference infact the 336mm by volume and weight are a lighter disc iirc.

Plus the pad area is bigger of the R models.

Braking obeys 3 main rules

clamping force.
leverage (disc size).
pad area.

I have run an s60r with both of these set ups and its only at repeated braking the differences show up a lot, but there is a smaller difference under normal braking.

Don't knock it till you've tried it dude

Don't have to, someone's done it for me.

[Ettienne]

I found thus just now, which is pretty much what I've just said. Bear in mind that R have larger pads and a better range of pads, which will give them an edge in initial application and the difference just gets bigger, plus R have larger vented rear discs. But as a budget option the xc90 336s are extremely good.

So what can 4-piston opposing calipers do for your ride, besides looking awesome? The number one performance increase occurs not when slamming on the brakes the first time (as previously discussed in the physics lecture) but, the second, third and tenth time. 4 pot calipers will react with much less brake fade than single or dual piston sliding calipers. It's because with larger calipers and rotors, heat dissipation is greater. This can be magnified with the use of sport brake pads and larger rotors of different composites. Having larger calipers with opposing pistons also means that the braking force will be increased with less pedal movement. A car equipped with opposing piston calipers and larger rotors will have a harder-feel brake pedal, and will emit more force on the wheels as a sliding caliper with less pedal movement. So in essence, will your car stop sooner with bigger 4-pot calipers up front? No. Will it stop more consistently after time, with less brake fade and a firmer, short throw brake pedal? If installed right, and tuned correctly, absolutely. And it still looks awesome.

[Biff]

I used to be the late break king but seems I'm losing my grip if 302's are good for me....
This cars going to owe me a fortune in a few years. Lol

[Wobbly Dave]

I've been using DS2500 on my C70 for many years including track days. You can after 6 hard laps of circuit racing -



at Oulton Park. I still want a BBK but for the road they are not needed IMHO.