Brakes. Spongy, no air bubbles.

MOT failed on brake pipe corrosion. Main rear lines changed at garage, front part of line all so changed, bleed through a couple of times with air pressure kit, no bubbles left, brake pedal still a bit spongy, pedal drops very slowly when engines running, not at all when off.
Do I have a master cylinder issue or ABS module fault?
Thoughts much appreciate.

retneprac said:

MOT failed on brake pipe corrosion. Main rear lines changed at garage, front part of line all so changed, bleed through a couple of times with air pressure kit, no bubbles left, brake pedal still a bit spongy, pedal drops very slowly when engines running, not at all when off.
Do I have a master cylinder issue or ABS module fault?
Thoughts much appreciate.

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Gravity bleed works best for me with Landrovers.

If you can't get a decent pedal doing that, check the master cylinder pushrod adjustment.

Not sure if gravity bleeding works with an ABS set up, any one know?

tottot said:

Not sure if gravity bleeding works with an ABS set up, any one know?

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Fair point. Never had one with ABS.

Going to try the gravity bleed method now a 3rd foot is available.

retneprac said:

Going to try the gravity bleed method now a 3rd foot is available.

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You don't need any feet for gravity bleed. Just attach a tube to the nipple, put the end of the tube in a jar, open the nipple, and keep the reservoir topped up.

My car has ABS and I can gravity bleed it. Ford Focus.

Check the flexis aren't ballooning

Rule out a failing Vacuum Pump - quick check is to pull the vacuum hose off the Servo while idling and see if you get much suction when you put your finger over it - it needs to be significant (not quite chrome off a trailer hitch!) enough to hold on to your finger. If it’s feeble then Vacuum pump is the culprit. Easy swap out.

One thing to quickly rule in/out.

retneprac said:

MOT failed on brake pipe corrosion. Main rear lines changed at garage, front part of line all so changed, bleed through a couple of times with air pressure kit, no bubbles left, brake pedal still a bit spongy, pedal drops very slowly when engines running, not at all when off.
Do I have a master cylinder issue or ABS module fault?
Thoughts much appreciate.

Click to expand...

sounds like master cylinder to me..time for a new one!

KISSMYAURA said:

sounds like master cylinder to me..time for a new one!

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Early days for that. If he has changed three brake lines, there is going to be masses of air in the system.

It will take several attempts, and several waiting periods in between, to get it all out.

Yes, in my experience a lot of air can hide in a Land Rover braking system. I find it best to let it settle overnight and have another go the following day.

What does the plastic pipe do that sits at the back on top of the master cylinder? Looks like a seal that’s split. Bit of rust, wet from too much fluid stilling out.

Recon you may have found the problem.

If there's air in the abs, you have to run the pump to get it out?

New master cylinder fitted, now the joys of purging the air out, bubbles coming up into the reservoir when peddle pushed, bled the system once, settling time whilst it’s pishing down. More later. Any tips on purging the master of air?

retneprac said:

New master cylinder fitted, now the joys of purging the air out, bubbles coming up into the reservoir when peddle pushed, bled the system once, settling time whilst it’s pishing down. More later. Any tips on purging the master of air?

Click to expand...

Same as above, take your time, go round the wheels on gravity bleed, keep pouring fluid in the top. You will get there in the end.

retneprac said:

New master cylinder fitted, now the joys of purging the air out, bubbles coming up into the reservoir when peddle pushed, bled the system once, settling time whilst it’s pishing down. More later. Any tips on purging the master of air?

Click to expand...

I use a sealy pressure bleeder, even then slow pedal depress and hold, then control release seems to do the trick.....
Especially with new MC, as you have to fill that first before the lines, I did a full brake line, MC, proportioning valve thingy replacement last year on the defender, ( see my build thread) filled and bled it up same day, just got to be patient,

Bled through again twice, all seems good. Went for the MOT retest.
Still failed on emissions. What’s next after doing a few of the normal things, Italian service, oil fortify added with oil change, fuel treatment. Suggested to burn a couple of tanks of premium diesel?
What else could I try next?
Am I getting into piston ring territory or am I still looking at oil and fuel treatments? Emission test attached. Should I remove the sticker with the emission data?
Guess it could all be down to the egr being blanked?

When you say Italian service.. what did you do?
My understanding especially for an older diesel, 3000rpm for a couple of minutes, after the exhaust is already hot
Is the egr clean?