Sh*** Brakes

[Alan Cherry]

Any advice from experienced sages out there most welcome.
I have a Rover 220 Turbo with awful brakes ( well awful lots of things, but I'm concerned about the brakes ). They sort of work OK, but could be sharper, and the pedal feels long and spongey.
Don't get me wrong - they did two hours at last weeks RCN round at the nurburgring, but they just feel awful and don't inspire confidence.
The set up is - Starting with the standard brake set up, plus I dumped the redundant ABS unit, and replaced it with T pieces to join pipes in same set up as the ABS unit. Links to the T pieces are with braided hoses - brakes no better. All flexible hoses are braided, so shouldn't be ballooning. rear discs and calipers are standard. Front Discs and calipers are from a Rover 623 with the holes redrilled to the 4 stud PCD. Standard master cylinder, - I tried replacing it with a brand new one, but just couldn't bleed the thing. Pads on the front are EBC either Blue endurance, or Yellow for uk use. The standard rear brake limiting valves are in line for each rear wheel.
All I can think of now is :-
1. Big mis match between master what master cyl is delivering, and what Rover 620 calipers are expecting.
2. Could the servo be affecting anything ?
3. Could the whole lot be flexing on the Bulkhead ?
Brothers proper race 220 has totally different set up, so I can't find any clues there - any constructive suggestions most welcome !

Thanks
Alan

p.s. am I expecting too much - are all Rovers like this. Even if the brakes are the same, but just feel differently, I'm sure a 'good feel' on the pedal would cut yards of braking distances !

[JamesH]

I had a Rover216 GTi road car and the brake were pretty good on that.

Few thoughts..

There could well be a problem with the new callipers vs the old master cylinder. Do you have figures for the calliper piston surface areas for both types - that would give some idea of mismatches (I think long and spongy would indicate the new callipers have a greater piston surface area)- if its big then there would be front/rear balance problems which you might be able to fix with adjustable bias.

Do the feel change after an initial press? (ie pumping up the system?)

I don't think braided lines are necessarily ballooning proof.

Doubt it's bulkhead flex - or all Rovers would have the problem.

Have you tried a set of standard road pads?

[Al Weyman]

If the calipers are bigger than the original fitted to the car but you are using the original master cylinder then that is your problem, fit a bigger one and all will be sorted. I had the same thing on my yellow car when I fitted massive Wilwood Grand National triple cylinder front calipers, fitted a special 1/8 inch bigger Wilwood job from the states and it bought them right back up. BTW look on Rally Designs site as they have a few Wilwood cylinders that can be fitted in a tandam standard set up as I am still using that complete with original vacuum assist servo and they feel fine, they did'nt have the one I wanted but Wilwood will give you a US guy who will ship to the UK.

[Peter Mallett]

Could be EBC pads. I won't touch them.

Also some brake calipers can expand under load. I used to run a set of (no names) but I couldn't get even braking out of them so switched to AP.

[bdwoody]

alan its a long shot but are the rotor vents on the inside or the outside on the originals the same as the 620 rotors ? i fitted set of rotors with the vents to the outside of the rim on my car and after 5 laps of brands the pedal almost went to the floor ! i changed the rotors back and the brakes were back to good again...
i agree with peter ebc pads bin em....

[Al Weyman]

That would be asumming it starts off good and gets worse woody in which case my first action would be to change the fluid to castrol SRF because I have tried them all and it has (IMHO) no equal and the only one that held up in my cars. My money is still on fitting a bigger master cylinder and while at it change to SRF fluid.

[Chris Y]

Originally Posted by Al Weyman

If the calipers are bigger than the original fitted to the car but you are using the original master cylinder then that is your problem, fit a bigger one and all will be sorted.

Agreed. It sounds like you're having to displace more brake fluid to get the pads to bite. That would result in the long pedal.

The sponginess... Well, I reckon it's this:

Originally Posted by Mr Mallett

Could be EBC pads. I won't touch them.

Agreed! A lot of drivers in my championship were running EBC yellows, mainly because they're cheap. However, I just couldn't get the feel right on them - the pedal was always spongy, and I was forever trying to bleed the brakes, trying different oil, etc. Went back to EBC and asked for different compounds, etc.

Eventually I threw in the towel and pleaded with Ferodo for help. They supplied me with some pads which are actually supposed to be for 'light formula cars' only, and mine's an 850kg saloon. I have to say though, I've never had brakes so GOOD on that car - good bite, consistent feel, and even, consistent stopping power.

After one race on the EBC yellows, the pads resembled Weetabix. The Ferodos look good and solid, and as you'd expect a racing brake pad to look like.

Sorry EBC, but I'd have to agree with others on this thread - ditch the EBC pads and look for alternatives from Mintex, Ferodo, or even Pagid.

[Alan Cherry]

Gents,
Thanks for the suggestions so far. brakes are consistent, and don't pump up, or get worse in use. I think the pads that I'm running are too hard, so softer pads would probably be the way to go, and I'll probably try a bigger bore master cylinder to see if I can improve the pedal feel.
The Blue 'endurance' pads have lasted 1x 2 hour event at The GP circuit at the ring, 1x 2 hour event at Spa, and 1x 2 hour event at the Nordeschleife, and still have some meat on them, so I suspect they are far too hard - perhaps I'll try yellows next time out, and reds in the Tintops.
Just hope a new master cylinder firms up the pedal. main reason for using EBC is they are available - last time I needed some pads, I tried to buy Mintex, but was quoted 3 months for a set for those calipers (not a high demand for endurance pads for a Rover 620 turbo Caliper - Ha Ha.
Suppose I should order things more in advance.
All I need now is details of the different Rover 220 Turbo master cylinders ( mainly Bore size - I think there are about 4 different models )
Al - The Tandem Master cylinders in the Rally Design catalogue are eithr 1" or1,1/16" Bore size which are enormous compared to the one on the car - may be too much more fluid being shifted !
Keep the suggestions coming gents !

[Peter Mallett]

Pads: I use Ferodo DS3000 (I think they've got a new reference now) on the front and Mintex on the rear. Fronts do about 4 hours max. If you're getting more than that you're running too hard. The main problem with EBC is the curing process. If you get it wrong they just fail, get it right and they're average at best. And a car weighing over 1 tonne is not funny with no brakes. Downside is I need to replace the discs every season.

[Al Weyman]

Do they do a master cylinder for a model without vacuum assist if so that should be a larger bore. Maybe you need something about an 1" big, the standard one on the Camaro is 1" and that original had a single sliding caliper up front and drums at rear so I would not have thought much different than what you are using. Also as you appear to be using standard road car bits are you using a sliding caliper because they crap! Was'nt you the guy I gave a pair of Astra brake brackets too? If so they will fit a standard spacing aftermarket 4 pot caliper and if you are using a road car sliding unit you may be wise to invest in some Wilwood Dynalight 4 pots or similiar. Road car brakes designs are usually designed for the one heavy brake scenario i.e. you drive down the motorway and may need to hit your brakes hard once in a hundred miles of motoring. In this scenario a slider is OK but use them hard and the pad will literally bend in the middle, I know I have tried and had special pads made up for the Camaro years ago by Mintex! Also spoke to a Mustang Historic racer who has to run them and he has exactly the same problem.

[GORDON STREETER]

[quote=Al Weyman]Do they do a master cylinder for a model without vacuum assist if so that should be a larger bore. quote]

You need a smaller bore without a servo !

[Alan Cherry]

Al,
Yes it's me with the Astra - still got it, but it dropped a valve at Silverstone last year, and haven't had time to fix it yet - working on the house, so having to make do with the Rover until I can find some spare time.
p.s. and you made the adrenalin adverts for the side of the car, plus some names for the back window !

[Al Weyman]

Yeah thast right I remember now but of course Astra bracket wont fit a Rover, Duh!!

[bdwoody]

more red wine vicar....i mean al !!!!

[Al Weyman]

Its an age thing, just turned 60 don't you know, man thats old!

[AU N EGL]

Originally Posted by Al Weyman

Its an age thing, just turned 60 don't you know, man thats old!

60s the new 30

[morninggents]

[quote=GORDON STREETER]

Originally Posted by Al Weyman

Do they do a master cylinder for a model without vacuum assist if so that should be a larger bore. quote]

You need a smaller bore without a servo !

Agree with Gordon. Surely the way to go to get better caliper action is to reduce the master cylinder bore size. Ditch the servo for track action.

[Al Weyman]

Sorry I cannot see that, the large cylinder will shift more fluid per inch of stroke. My pedal was almost down to the floor I went up to the 1 1/8 inch one and its perfect. This is the piece I used and is available in different bores. http://www.wilwood.com/Products/006-...TCMC/index.asp

BTW did'nt Gordon once have a near disaster with a dual master cylinder set up which is one reason I prefer the safety of a tandam cylinder.

[JamesH]

I agree with Al - I would think that with an increase in calliper piston surface area, you need to increase the master cylinder surface area to compensate - going the other way means a longer pedal travel, although pressure will increase, you cannot shift enough fluid to actually apply the brakes in the available travel of the pedal.

James

[GORDON STREETER]

If you can stop the car all well and good. What I was picking up on was what Al said as regards replacing the master cylinder with the same bore without the servo.
Fair enough if you have different bore or multi piston calipers, but you have to come to a compromise as regards pedal pressure.
Have you ever tried to stop a servo assisted road car without the engine running when the vacuum tank is empty ?

[Al Weyman]

No I didnt mean that what I meant was that a none servo cylinder will be a different size and I am talking standard kit here for example on the Camaro you can get them with servo or without as everything is an extra and the none servo cylinder is a different size.

[Rovcoup]

Alan this is a known problem with the calipers your using you need your brothers roversport master cylinder (aka landrover defender) i could dig out the part number for you.

[JamesH]

Put us out of our misery - is that a larger or a smaller bore than the original item?

James

[Al Weyman]

My money will definitely be on it being larger!

[bdwoody]

more pressure to the caliper = smaller cylinder .bigger cylinder = more pedal effort.