Citroen Bx Front Calipers On Rear Beam Of 205 Gti

[GTI_Lee 0]

hi i have just been and bought a 205 gti tonight

 

the lad has told me that it has citroen bx front calipers on the rear (bx's have the handbrake on front so will be able to use)

 

has anybody heard of this trick?

 

also wandering what handbrake cables i would use... bx ones or normal gti ones

 

thanks lee

[GTI_Lee 0]

i did do a quick search and found someone talking about having to change the seals or having to use different brake fluid?

 

but i cant find anymore threads.. anyone here available to help

 

thanks lee

[Mongo 0]

i did do a quick search and found someone talking about having to change the seals or having to use different brake fluid?

 

but i cant find anymore threads.. anyone here available to help

 

thanks lee

 

they probably use LHM fluid instead of the normal dot brake fluid, this would explain in the change of caliper seals. Don't see the need in fitting larger calipers to the rear, since they hardly do much braking on such a lightweight FWD car like the 205...

[GTI_Lee 0]

the car has got a hydraulic hand brake and ill be doing night rallying init pretty soon.

 

so completely gut the system of dot fluid and use LHM fluid instead and it will be fine yea?

 

anyone know about the handbrake cables aswell how to getting around them?

 

thanks lee

[inferno 1]

they most definatly do use lhm fluid. ive never replaced the seals in these before, but really dont see the point in using them over standard gti ones.

 

just realised you said FRONT brakes too... id suggest you try the brakes on a BX and look how easy they stop, the design is whack, i guess if you plan to regularly overhaul them it would be easyer to do than a gti one. thats about it.

Edited April 25, 2007 by inferno

[GTI_Lee 0]

its how i have bought the car tbh mate.

 

i know the rear beam has been replaced with a disc beam and he told me he fitted these bx calipers.

 

i think im gunna struggle with the handbrake cable tbh i bet they will be a different way of attaching them.

 

if it does become a problem then ill just buy some gti ones.. are the exspensive?

 

thansk lee

[inferno 1]

do you have photos and ill be able to varify whats been done. fitting bx front handbrake cables is a pig, never seen them on a 205. are you sure there not ZX calipers? ie the same as a gti?

 

if fluids not leaking dont mess with it untill you have worked out whats been done, i cant remember which way round leaks, dot 4 in lhm systems or vica versa?, a hydro handbrake would suggest its running dot 4 as again ive search and never seen an lhm compatible hb seal kit.

Edited April 25, 2007 by inferno

[Rob Thomson 6]

I looked into doing this a couple of years ago.

 

Two reasons....

 

1) Makes a hhydraulic handbrake much more effective (much bigger pistons)

 

2) Balances the brakes if you're running big front brakes. With GTi-6 fronts on my 309 I couldn't get enough rear braking even with a bias box. Again, bigger pistons at the back would have helped.

 

Someone on here (James Lumley I think) ran them using DOT whatever fluid and the original seals with no problem, but I was always a bit cynical about it. I couldn't find any suitable seals to rebuild them with, which is why I gave up on the idea.

 

As far as I know the handbrake cables are exactly the same.

[Baz 421]

i know the rear beam has been replaced with a disc beam and he told me he fitted these bx calipers.

 

Jut a shot in the dark, maybe he said 'Bendix Calipers' ??

 

What width are the discs, are they vented? I've heard of using 1.6 GTi pad carriers on the rear with a vented disc.

Edited April 25, 2007 by BazGTMi

[Rob Thomson 6]

The pad carriers are all interchangeable IIRC. So you can run vented rear discs regardless of which caliper you use.

 

One of the things that pisses me off most in life is people who only upgrade their front brakes, and think that fitting 18-pot calipers and 17" discs will make their car stop on a sixpence. Will they bollocks. Big brakes are about fade resistance and (possibly) improved modulation.

 

The factory bias is very safe (ie. towards the front). You can make a car stop much better if you take away some of that margin of safety by increasing the rear braking effort.

[jackherer 543]

Don't put LHM in a 205, not a good idea at all.

 

If its running BX calipers and normal brake fluid without leaking then its had the seals changed as brake fluid eats citroen LHM seals.

[GTI_Lee 0]

right.. he was in the middle of doing the car up, it has citroen bx calipers on the back

 

he hasnt used them yet because i bought it off him before he had time to finish

 

sooo the handbrake cable are thye same.

 

the best idea will be to use dot 4 fluid then yea?and just hope the seals will be fine.

 

why cant i use lhm fluid on a 205?

 

thanks people

[tom_m 0]

because LHM seals are not compatible with dot 4 fluid and vice versa, doing either way round is just plain dangerous!

[GTI_Lee 0]

ive spoke to a local garge and they said they have used dot 5 fluid in bx calipers before and its been fine.

 

also where can i buy the brake lines / t-pieces / male / female ends for the car? looking for them for this week end?

 

thanks lee

[inferno 1]

IMO youd be better off converting back to standard rear discs n calipers. You cant just run dot 5 in bx calipers, to have done that youd have needed to fill the bx suspension/brakes/steering system with it, and im pretty sure that would cause problems.

 

quoteing from bottles of fluid...

'peugeot brake and clutch fluid is the approved specification for use in pug vehicles. it meets with requirements of FMVSS no. 116 dot 3 SAE J1703 ISO 4925 and can safetly be mixed with other fluids conforming to these regulations.It cannot be used in certain citroen models or other vehicles requireing a mineral based fluid.'

 

LHM spec

'AFNOR NFR 12-640M. _ISO 7308

NON HYGROSCOPIC

WARNING

Mineral based hydraulic fluid suitable for braking and suspension systems painted or marked in green. This product is NOT compatible in systems using synthetic or semi synthetic fluids.'

 

the only way to safetly run an LHM rear braking system IMO is to use the parts from the system on say a bx/xm/xantia. this would include a high pressure pump, a resevoir, rear shocks (they power the rear brakes depending on hight at time of braking, brake actuator, front and rear calipers, new brakelines throughout (there higher pressure and need thiner lines), theres about 3 regulators and pressure safety deviced on the brakes side of the system, an accumulater, and probably a few bits ive missed.

 

the citroen LHM system is very good. but the 205 setup is good too. unless your planning using a bx 4x4 rear end/405 mi16x4 rear end, i really wouldnt bother with lhm. ive spend way too long thinking about it myself, and decided aginst it.

[jackherer 543]

Brake fluid will eventually destroy the seals and it will leak, just fit 205 brakes.

[inferno 1]

just found this...

 

We do not recommend using DOT 5 fluid in any racing applications. DOT 5 fluid is not hygroscopic, so as moisture enters the system, it is not absorbed by the fluid, and results in beads of moisture moving through the brake line, collecting in the calipers . It is not uncommon to have caliper temperatures exceed 200 F, and at 212 F, this collected moisture will boil causing vapor lock and system failure. Additionally, DOT 5 fluid is highly compressible due to aeration and foaming under normal braking conditions, providing a spongy brake feel. DOT 5 fluid is best suited for show car applications where its anti-corrosion and paint friendly characteristics are important.

 

so it mite work but your brakes will feel crap!

[Baz 421]

Dot 5, Dot 5.1 or both?

[Rippthrough 98]

The pad carriers are all interchangeable IIRC. So you can run vented rear discs regardless of which caliper you use.

 

One of the things that pisses me off most in life is people who only upgrade their front brakes, and think that fitting 18-pot calipers and 17" discs will make their car stop on a sixpence. Will they bollocks. Big brakes are about fade resistance and (possibly) improved modulation.

 

The factory bias is very safe (ie. towards the front). You can make a car stop much better if you take away some of that margin of safety by increasing the rear braking effort.

 

 

That depends on where you use the car, and what tyres you have fitted.

[inferno 1]

dot 5 and dot 5.1 are different. dot 5.1 is good for regular brakes. didnt look into dot 5.1, but google was throwing up some good info in general and 5.1 got a mention.

[jack biscuit 0]

i thought dot 5 fluid was silicone, and so is lhm.. so it's the same stuff??

[Baz 421]

i thought dot 5 fluid was silicone, and so is lhm.. so it's the same stuff??

 

Dot 5 is a silicone fluid, LHM isn't.

 

LHM spec

'AFNOR NFR 12-640M. _ISO 7308

NON HYGROSCOPIC

WARNING

Mineral based hydraulic fluid suitable for braking and suspension systems painted or marked in green. This product is NOT compatible in systems using synthetic or semi synthetic fluids.'

[jackherer 543]

i thought dot 5 fluid was silicone, and so is lhm.. so it's the same stuff??

 

Citroen developed LHM specifically for the purpose. The owners manuals say that engine oil is OK to use in emergency situations when no LHM is available as this is the commonly available fluid with the closest properties, which gives you some idea how different from brake fuid it is.

[GTI_Lee 0]

ok thanks for the replies people.

 

i was thinking by time i got through all the hassle with the handbrake cables / fluid etc...... i might aswell just put 205 rear calipers back on..

 

thanks lee

[Rob Thomson 6]

That depends on where you use the car, and what tyres you have fitted.

On the road with black round ones?

 

Back to the LHM thing... To be safe you have to re-seal the calipers. You can easily re-seal the handbrake side of the caliper with the seals from a GTi rear caliper. I'm sure you could find suitable main piston seals somewhere, but it's knowing what to get them off...

 

Going purely from memory, the BX calipers have 50mm pistons. I think the 1.6 front calipers have 48mm pistons, so you can't use them. But there's got to be a car out there somewhere that uses 50mm pistons with seals of a suitable width.