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Braking Broken - Suspension/Brakes/Wheels/Hubs/Steering/Geo - The Lotus Forums #ForTheOwners Jump to content


Braking Broken


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Driving home tonight, brake warning light came on and I lost all servo assistance, got home (very slowly) parked up on the drive, switched off and turned ignition back on. I can hear the pump running (about 30 secs) then it switches off, but pedal is rock hard and warning light is still on.

Any ideas anyone?

Jez

Mean Green S4s

I think therefore I am - Descartes

I'm pink therefore I'm spam - Eric Idle

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OK! my car seems to be a bit of an odd one.

It's an S4s but it doesn't have the accumulator or any of that gubbins, it's got the system from later GT3's so there's a big black vac pump in the boot

There are a few other odd things about the car that lead me to think this may have been one of Lotus development cars as the gear change is also from later V8's

It all seems factory fit and I can't imagine an owner fitting these sorts of items.

Jez

Mean Green S4s

I think therefore I am - Descartes

I'm pink therefore I'm spam - Eric Idle

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Sounds like pump not working or leak in hose, as long as pedal is hard then its not a fluid leak, odd car spec??

have fun!

Dont worry,be happy.............

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HI

If it has different brakes to the normal spec your very lucky because they are rubbish. Sounds like the servo side of your brakes have failed. Start at the simple side first check when you first turn the car on for the pump in the boot running, if it is running take a pipe off it and check it is actually creating a vac. If it is producing a vac then check the pipe is ok all the way to the front by removing the pipe at the servo in the front compartment and check the pipe is sucking for a vac again. If it isnt your pipe is split if it is your Servo or non return valve are US.

Is the pedal rock hard all the time now but the brakes still function but you have to stand on the pedal? That is the classic sign of servo problems.

Regards Mike

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Cheers Mike

Pump is running, though not taken hose of to see if vac is generated, and yes the pedal is rock hard and the brakes still sort of function i.e. stand on the pedal to bring the car to a slow stop.

Will pull the hoses later to see whats happening.

Jez

Mean Green S4s

I think therefore I am - Descartes

I'm pink therefore I'm spam - Eric Idle

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  • 3 months later...

Still not sorted 100%

The pump seems to be working OK, but the brake warning light remains on and the pump runs probably a bit more than it should, but otherwise braking is fine.

I'm looking for a new brake servo and master cylinder assembly, the one on the car is a bit rusted underneath and suspect this is the root cause of the issue.

Jez

Mean Green S4s

I think therefore I am - Descartes

I'm pink therefore I'm spam - Eric Idle

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The mounting bracket is for deffo V8 It does look like a V8 set up.

Does the master cylinder have Bosch 23 moulded in the casting? The servo may have a sticker on it which will also state Bosch.

I can supply part numbers if required

Is your car a late S4s?

Does it have ABS?

Hope this helps

Regads Mike

Edited by G_Reaper2
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The mounting bracket is for deffo V8 It does look like a V8 set up.

Does the master cylinder have Bosch 23 moulded in the casting? The servo may have a sticker on it which will also state Bosch.

I can supply part numbers if required

Is your car a late S4s?

Does it have ABS?

Hope this helps

Regads Mike

Mike

Can't see Bosch anywhere, only Bendix

Mine is actually an early S4s 22nd off the line.

Seems my car was a test bed for Lotus

Ive got V8 braking system, sport 300 chassis, V8 gear change, and a few other bits not "standard" on S4s cars.

Jez

Mean Green S4s

I think therefore I am - Descartes

I'm pink therefore I'm spam - Eric Idle

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Did you check the vacuum pump or line from the vacuum pump? They still used a vacuum actuated system without the accumulator didn't they? I lost the waterpump/vacuum pump belt on my Esprit a few years back and it was a very hard pedal with little effect on brake bite when I stood on the pedal. I do realize that the later models didn't use the mechanical pump and went to an electric pump but if you lost vacuum to the booster, it would behave the same way I believe. Just a thought.

Artie

89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

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OK The V8 I inspected was a 2000 model year it looks like Bosch must have bought the Bendix company at around this time. Your master cylinder looks identical to a V8 master cylinder the only difference being that Bosch is moulded into the cylinder where the Bendix is on your MC. It stands to reason that the servo will be a Bendix. I will try and find out what they are also used on. Does your car have ABS???

Cheers Mike

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