Can't get a hard brake pedal

[Harbir]

Despite repeated flushes with ATE fluid (by the dealer), I can't get a hard brake pedal.

Its squishy. If I pump it, it gets hard, but if I don't relieve the pressure at the pedal, it slowly squishes down and returns to its softness.

Is this a TADS deal? Or do I need to do a flush myself and do it a certain way?

i'd really appreciate some help here. a soft squishy brake pedal on a car that isn't good for anything except direct, immediate driving responses is quite egregious, IMO.

Any advice would be very welcome. I did buy a pressure bleed kit from CDOC but haven't opened it yet.

Thanks!

[karajabola]

master cylinder? slave cylinder? Is the fluid level changing after repeated brake applies? I'm thinking leak here or a problem with the booster.

[British_Marques]

Originally Posted by Harbir

Despite repeated flushes with ATE fluid (by the dealer), I can't get a hard brake pedal.

Its squishy. If I pump it, it gets hard, but if I don't relieve the pressure at the pedal, it slowly squishes down and returns to its softness.

Is this a TADS deal? Or do I need to do a flush myself and do it a certain way?

i'd really appreciate some help here. a soft squishy brake pedal on a car that isn't good for anything except direct, immediate driving responses is quite egregious, IMO.

Any advice would be very welcome. I did buy a pressure bleed kit from CDOC but haven't opened it yet.

Thanks!

Try the power bleeder, the rears and then the fronts, buy extra fluid to get it done.

[codingparadox]

Someone once told me an easy test.

Press the brake pedal hard, and then hold that amount of pressure. If the pedal slowly sinks to the floor, it's a hydraulic problem (i.e. master cylinder is toast or you have a leak somewhere). If the pedal stays put, but it's deeper than you want, it means you have air in your lines.

I applied this test to my SM, found that the pedal continued falling. Changed my master cylinder. Sho' 'nuff, all was well.

[dasmoofler]

Try to find Tesprit's post on the subject - something about having to turn the calipers upside down to get all of the air out.

[British_Marques]

You really do not need to turn your Elise up-side-down. The first time it was done the front end was elevated about 4 inches. Now I just park. A couple of mason jars, some airline tubing, pressure kits and the adapter that goes on our master cylinder, and a friend that can listen to your directions when it comes to pumping the pedal. Unless you really have a failed master cylinder, it should just be air in the line. It is a great idea to replace the fluid every year as it absorbs moisture. Brakes are good, need to stop as well as we accelerate.

[Roger]

Harbir - are you sure it's not just that the feel is softer than a lot of other cars? Or do you have what codingparadox describes?

[rxliam]

Harbir,

Sorry you're having brake problem.

If the Elise is anything like the Miata, I'll do it the old fashion way, I'll get a buddy for an extra set of hands and extra bottle of fluid and do the following:

1) compress-hold-brake
2) squirt-tighten-bleeder valve
3) release-brake
4) untighten-bleeder value.
5) repeat 1) - 4)

Be sure to check the brake fluid reservoir and add fluid if need to.

Also, be sure you are bleeding your lines in the correct sequence, from farthest away from the cylinder to the closest. Usually, the longest line will have the air. After doing all four lines, if you are anal about it, repeat 1 - 4.

[glb]

Originally Posted by Harbir

I can't get a hard brake pedal.

Is it too soon for the "add Viagra to the system" joke?

[TimMullen]

Originally Posted by British_Marques

You really do not need to turn your Elise up-side-down.

Not the car, just the calipers.

The front calipers have two pistons/cylinders. The fluid enters at the top of the inside piston/cylinder, flows through the cylinder and out the bottom via a tube to the bottom of the outside half of the caliper. Then through the cylinder and out the bleed tube on the top outside half. If there is air in the calipers, it can remain in the inside half no matter how much bleeding you do.

To vent any air trapped in the inside half, you have to remove the caliper, flip it upside down so that the "cross-over tube" is now at the top. Then bleed some fluid through the caliper - which should move the air to the outside half. Then flip it back upright (re-mount it) and continue to bleed it - since the air is now in the outside half, it should come out the bleed screw.

As to the original post - if the dealer is bleeding the system, did they use the Lotus Scan Tool to put the ABS into "bleed mode" - if they didn't and you have air trapped in the ABS, you could still be getting problems.