Brake bleeding

[mike.c1979]

Hi all

Put the Porsche calipers etc on the car today and bled the system with eezibleed but it dosnt seem to have worked as the pedal is spongy. I bled drivers side front, passenger front, drivers rear and passenger rear in that sequence. I waited for all of the air bubbles and old fluid to clear through the piping and tightened everything up.

Im unsure whats up to be honest.

Any ideas?

 

[stewbie55]

I think you're meant to bleed them in the diagonal order as they're dual circuit brakes. Master cylinder may also need bleeding.

 

[tom167]

thats the wrong order, start with the furthest away from the reservoir, so iir n/s/r on a leon

 

[godber225r]

bleed closest to master cylinder first then the opposite side rear, then front and the opposite side rear, then master cylinder. I would do a fluid change wile your at it and bleed the clutch too. cant go wrong then.

 

[godber225r]

Go on search and type in '225 clutch' and read my thread i started last week when i wanted to know all about this, tells you all you need to know about bleeding the brake/clutch system it helped me a treat and it works 100%

 

[Willie]

Mike

I'm going to be doing a guide on this as there is alot of miscomceptions about this and its becoming very dangerous. theres a few correct statements in this thread but too many wrong ones aswell.

When bleeding your brakes for all the cost buy new brake fluid. Brake fluid is hydroscopic (basically sucks water out of the air). this lowers the Boiling Point of the fluid and makes it ****.

So remove all the fluid out of you reservoir

Replace this with new fluid and keep and eye on the level.

Starting with the Master cylinder bleed these (2) first, then inturn bleed front wheel then diagonal rear wheel.

Then other front, then diagonal rear wheel.

Then onto the clutch (which require the clutch to be depressed for this.

Don't pressure up the nipple then open, just crack the nipple and allow a controlled flow of fluid till you evacuate all the old fluid and get air free fluid out.

Hope this helps

 

[tom167]

No, no its definately furthest calliper first. For example, if you bleed the n/s/f until its clear of air; but there's air trapped in the line to the o/s/r, it may very well flow back into the line to the n/s/f rendering bleeding it completely pointless. Do furthest away, to make sure no air can flow back through the system. And if you want to do it really properly, actuate the abs pump to bleed that aswell.

 

[Willie]

No, no its definately furthest calliper first. For example, if you bleed the n/s/f until its clear of air; but there's air trapped in the line to the o/s/r, it may very well flow back into the line to the n/s/f rendering bleeding it completely pointless. Do furthest away, to make sure no air can flow back through the system. And if you want to do it really properly, actuate the abs pump to bleed that aswell.

Tom your talking pish here bud, please don't risk others safety by speaking about what you think is correct. This could be fatal.
If you want to do it this way to your car and your mates cars, go on.

 

[UncleFester]

Quite honestly for what a garage charge to do the job and on the basis it's a fairly important safety feature - just take it to a specialist to get it done who WILL do it properly.

 

[tom167]

Tom your talking pish here bud, please don't risk others safety by speaking about what you think is correct. This could be fatal.
If you want to do it this way to your car and your mates cars, go on.

Yeh thats fine, i'll print out the mercedes document that tells us this while i'm at work later and settle this then

 

[Muttley]

A couple of comments here, hopefully to add some value.

Use a pressure bleeder (Easibleed or similar). This way you shouldn't run out of brake fluid, and you remove the risk of damaging the master cylinder seals.

Replace the fluid every two years at the outside. It is hygroscopic - attracts water out of the atmosphere - which eventually degrades its performance (the pedals go soft).

I would not empty the system first, just add new fluid to the reservoir. There is some value in emptying most of the old fluid out of the reservoir first, but not draining it dry, that is guaranteed to get air in the system. Bleed at each point until the fluid changes colour.

Many manufacturers advise bleeding farthest caliper first, but not all. The matter is complicated as the fluid first goes through the ABS system and pipe runs are not simple to visualise. It would be best to discover the SEAT recommended sequence for your car and follow that. Mercedes practice does not map onto Seat Leon requirements.

It is most important not to forget the master cylinder (two bleed points) and the clutch system which shares the same fluid reservoir (clutch slave cylinder and master cylinder).

 

[tom167]

The reason for bleeding the furthest away is because its the longest line, unless a leon's master cylinder is in the boot, its still the same practice, for the same reasons.

I'm not having someone telling me i'm "talking pish" when i've had four years of training and do it for a living. Not just mercedes, but any manufcaturer i've worked for has had this practice.

 

[Willie]

The reason for bleeding the furthest away is because its the longest line, unless a leon's master cylinder is in the boot, its still the same practice, for the same reasons.

I'm not having someone telling me i'm "talking pish" when i've had four years of training and do it for a living. Not just mercedes, but any manufcaturer i've worked for has had this practice.

Fair enough

 

[mr_cool]

IIRC in elsawin it describes bleeding FRONT FIRST for one type of brake system AND desribes bleeding REAR FIRST for a different system.

 

[DPJ]

As I understand it, its nearest then furthest for each diagonal line for Vag. (Can't remember which side you start on without checking). If you do furthest first, there's a risk of airbubbles fron 'nearest' being drawn into the long lines..

 

[Willie]

As I understand it, its nearest then furthest for each diagonal line for Vag. (Can't remember which side you start on without checking). If you do furthest first, there's a risk of airbubbles fron 'nearest' being drawn into the long lines..

But in Mercedes.................lol

 

[LEE69]

As I understand it, its nearest then furthest for each diagonal line for Vag. (Can't remember which side you start on without checking). If you do furthest first, there's a risk of airbubbles fron 'nearest' being drawn into the long lines..

Brake system; bleeding, vehicles with and without ABS Mark 20 IE
Brake system: bleeding with the SAT 1175 filling/bleeding unit
Special tools, workshop systems, testers, measuring instruments and auxiliary items required



◆ SAT 1175 filling and bleeding equipment
Note:

In vehicles with ABS, the bleeding of the brakes is carried out in the same way as in vehicles with a conventional braking system.

‒ Connect the SAT 1175 filling and bleeding equipment.
‒ Open bleeding screws in the prescribed order and bleed the air from the brake callipers.
Bleeding sequence

1 - Rear right brake calliper
2 - Rear left brake calliper
3 - Front right brake calliper
4 - Front left brake calliper
Vehicles with ABS or ABS/EDS

Note:

A test drive must be done after completing the bleeding. During this test drive, at least one ABS activation must take place.

Replace brake fluid

=> Maintenance

Previously bleeding the brake system, if one of the brake fluid circulation deposit chambers is completely empty (e.g. due to leaks in the brake system)

Bleeding sequence

1- Bleeding the front left and right brake callipers simultaneously
2 - Bleeding the rear left and right brake callipers simultaneously
‒ With the bleeding bottle hose, leave the bleeding screws open until brake fluid comes out without air bubbles


OR


Brake system; bleeding, vehicles with ABS Mark 60
Brake system: bleeding with the SAT 1175 filling/bleeding unit
Special tools, workshop systems, testers, measuring instruments and auxiliary items required



◆ SAT 1175 filling and bleeding equipment.
‒ Connect the SAT 1175 filling and bleeding equipment.
‒ Open the bleeding bolts according to the recommended sequence.
Bleeding sequence

1 - Front left brake calliper
2 - Front right brake calliper
3 - Rear left brake calliper
4 - Rear right brake calliper
‒ With the hose connected, leave the bleeding screws open until the brake fluid comes out without air bubbles.
Note:

A test drive must be done after completing the bleeding. During this test drive, at least one ABS activation must take place.

Replace brake fluid

=> Maintenance

Previously bleeding the brake system, if one of the brake fluid circulation deposit chambers is completely empty (e.g. due to leaks in the brake system)

Bleeding sequence

1 - Bleeding the front left and right brake callipers simultaneously
2 - Bleeding the rear left and right brake callipers simultaneously
‒ With the bleeding bottle hose, leave the bleeding screws open until brake fluid comes out without air bubbles.

 

[Willie]

No clutch or MC then?

 

[LEE69]

Nothing was mentioned in that i'll have alooksy.

 

[LEE69]

Clutch system: air bleeding
Special tools and workshop equipment required

t Brake bleeder -SAT 1150-
– Brake fluid specification: → Rep. Gr.00.
Note!The system does not need to be pre-filled.
– Connect brake filling/bleeding -SAT 1150-.
– Connect the bleeding hose to the collecting bottle of the brake bleeding device.

– Fit the hose -A- in the bleeding device -arrow-.
– Place lint-free cloths under the bleeding device.
– Apply 2 bars pressure to the system.
– Open the bleed valve carefully.
– Let about 100 cm3 of brake fluid come out.
– Press the pedal to the floor 10 to 15 times and release quickly to expel all small air bubbles.
– Let another 50 cm3 of fluid come out.
– Close the bleeding valve.
– After bleeding, the clutch pedal must be pushed several times.
– Check brake fluid level in the reservoir. If necessary top up to the correct level.