Bleeding Brakes

[Blue4Ice]

Now my brakes aren't causing me problems but they do need a fluid change

I have a 90SE which doesnt have ABS so I am hoping its going to be a simple job. I read the guide on LEW but that is for a model with ABS. What steps do I or dont I have to do?

Any advice appreciated

[Jonathan]

Not done an Esprit but done a few other cars. You NEED a clear plastic hose line which will fit over the bleed nipples to see air in the fluid.

(EDIT : Tell a lie I have partially bled an Esprit but not fully when I removed the calipers.)

All I have done is one at a time slackened each of the bleed nipples on the calipers and bled fluid from the system by depressing the brake pedal.

Small pipe on the nipple into a jar, action-pumpo, move onto the next one.

Once the fluid is purged, close all the nips, re-fil the reservoir and best leave the fluid settle but with the cap unscrewed (have a cuppa) so the natural air in the system can float away - then do one of 2 things:

1) Get another bod to pump the pedal or,

2) Get an easy bleed (yes they do work but mine seemed to airiate the oil so I went back to the 2 man method)

There should be a correct bleeding order, I usually start at the longest caliper away from the reservoir 1st (ie the back). Open the nip and prep a tube and catch tank like when you purged. Get your spare bod to pump the pedal repeatedly until the fluid coming out of the caliper has no air in it (ie nice and clear) - you can relaim this fluid you just dumped but to be on the safe side I usually tip it into the waste pot.

When there is no air, ensure the bod has their foot right down on the pedal and quickly shut the nip off (beware of suck back, moment you see the fluid stop coming out of the caliper shut the nip off).

Ensure the reservoir is constantly topped off and the fluid is 100% un-contaminated.

Rinse and repeat on 4 corners (owrking in to the shortest line which is usually the front o/s). Pedal should be firm, if it's not one of the lines has air in it so you need to repeat the process of bleeding.

---------------------

The other way is to flush the system without draining it. If you do regular brake fluid changes with the same fluid type this is much easier. Same principal but top the fluid up with new stuff as you bleed until you can see the new oil coming through - you'll use a lot more fluid this way but it's pretty much garaunteed not to cause problems as you're never introducing air into the system in the 1st place.

Some systems (like the S1 Elise) this method is gold becuase the front calipers are such a pig to bleed and need removing.

Edited March 9, 2006 by Jonathan

[Blue4Ice]

Thanks for that. I have done the second method before and will more than likely do that again as it seemed ok on other cars i have done it on

[Jonathan]

Yeah it is fine afaik - I'd only bleed the thing dry if I had any ideas that the fluid was contaminated or very old. As long as the pipes are intact you should know the brakes are getting bad when the pedal is spongy and fades in long braking from speed.

Secret is with things like this is to get in there and have fun doing these simply jobs on your own which is the idea of the LEW guides...if you do this regularly every year or so you can have it done in under and hour.

No need to buy the guchi stuff either unless you're on the track and you change regularly - standard DOT4 fluid is DOT4 fluid.....it all comes from the same tap anyways I reakon and has to conform to the same standards.

[pitstoppete]

if you have an easybleed, try filling the reservoir right up, then use the easybleed as normal, but with no fluid actually in the bottle. just top up when low. use about 20psi ish

[Jonathan]

Pete - ever find it introduces air into the system ?

When I was doing the Elise I could not get it clear until the old man helped and done the pedal pumpy thing instead of using the EZbleed....I am convinced it somehow introduced air into the fluid - when the pressure was off you could see bubbles of air inside the fluid expanding

[Blue4Ice]

I am changing my hoses at the same time to a goodridge setup. I ended up going for the Castrol Super Reponse as on the LEW lubricant page. All being well my brakes should feel a bit more like they are actually going to stop me!

[molemot]

There is another way - bleed from the caliper back to the master cylinder. Use a large syringe full of fluid, attach it to the bleed nipple with a suitable piece of tube, open the nipple and squirt away. It was the only way to get the air out of the braking system on the aeroplane I used to own - an Airtourer Super 150 - bleeding it the orthodox way always left air in it. Just a thought for the truly intractable spongey system.

[pitstoppete]

use the easy bleed as i said, and dont let the master cyl. go really low. top it up like after every caliper u bleed. its no trouble. using fluid in the easybleed makes it froth up a bit,as it transfers to the reservior, so leave that bit out. works atreat.

[ragingfool35]

I used one of these babies. Made a it an easy one man job. Just hook to each caliper (one at a time) and continuously fill the resevior with new fluid. When clean fluid comes out of the caliper, move on to the next

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Edited March 10, 2006 by ragingfool35

[Jonathan]

There is another way - bleed from the caliper back to the master cylinder.

<{POST_SNAPBACK}>

Yup I resorted to that on the Elise, depends on the pipework if it'll work or not, some air traps simply don't want to move, but it can work.

[rens914]

And when your at the job replace the fluid for dot 5

rens

[Blue4Ice]

And when your at the job replace the fluid for dot 5

rens

<{POST_SNAPBACK}>

Unless your changing the whole system (i.e. all pipework, cylinders, the lot) I thought this was bad as DOT5 is made up of a totally different material to DOT 3,4 and 5.1. Isnt DOT 5 synthetic?

[Jonathan]

DO NOT put dot 5 into the car, Dot 5 fluids are silicone based and whilst have a higher temperature boiling point they will bugger up the seals for good. Use non-silicone based fluids or you might find yourself in the next wall.

States in the user maunal Dot 4 ONLY (yes with the bold bits).

They Stuck 5.1 into my Elise when it was last done but unless you're tracking the car (ie doing hard braking every 10 or so seconds for a long period) then I wouldn't bother. I believe 5.1 is glycol based so it is safe to use again the only difference is it's boiling point - if you can get it fine, if not I wouldn't worry.

[sanj]

DOT 5 is silicone, and should only be used to shine your tires. Or tyres.

DOT 5.1 is a synthetic that can be used in place of DOT 3 or DOT 4, hence is OK to use.

DOT 4 is what it came with, and the minimum spec for the system.

[ragingfool35]

here is a very good overview

http://www.xs11.com/tips/maintenance/maint1.shtml

[Blue4Ice]

here is a very good overview

http://www.xs11.com/tips/maintenance/maint1.shtml

<{POST_SNAPBACK}>

Thats an interesting read