Ok so I have undertaken the job of replacing the master cylinder in my disco 3 due to the brake pedals excessive travel all the way to the bump stop in order to slow my vehicle down.
Prior to this I thought the brake lines had trapped air in them and did a full flush with new dot 4 fluid.
All lines were bled and still the problem persisted.
Therefore master cylinder got changed out for a new Britpart replacement and a full bleed again taking in also the abs bleed with my diagnostic icarsoft tool.
Thinking this was the solution to my problems I am very disappointed as the problem is still there.
I disconnected the vacuum line with engine running and noted that there was good vacuum going to the booster so I'm now thinking what next???
Anyone experienced similar problems and if so how did they overcome them?
Pretty sure there are no fluid leaks as the master cylinder level was at maximum mark with no noticeable drop in level over the past 12 months.
Also when the engine is off the pedal feels as firm as can be, it's only when the engine is running that the pedal sinks all the way.
Looking forward to finding some help with this one!!
Long shot, but I don't suppose you replaced the front calipers before the pedal problem started? I just did this and mixed up the calipers and installed the left on the right and visa versa. This puts the bleed screw at the bottom, trapping air in the caliper. No amount of bleeding will get the air out.
Other than that, have you tried a pressure bleeder?2006 SE 4.0 V6 with rear locker
21st Jun 2023 4:35 pm
STV
Member Since: 26 Feb 2023
Location: UK
Posts: 26
The calipers have not been changed and I have not tried pressure bleeding.
I think I may have to try this though just to rule it out.
Another possibility I was thinking about was that when I used my diagnostic tool to do the ABS bleed there was only noticable sound coming from the ABS unit whilst bleeding the right hand front and right hand rear calipers.
Is it possible air could be trapped in here? And could it mean my ABS unit is defective?
Before I figured out what I had done, I ran the abs bleed routine using the IID tool. It seemed to not run the pump on some of the wheels. In this video at 6:20 he says the IID bleed routine "didn't do anything for the first two wheels", so that might be normal for the abs bleed routine.
in the end, he just ends up pressure bleeding the system.
Are you able to use your tool to manually activate the abs solenoids?2006 SE 4.0 V6 with rear locker
21st Jun 2023 5:27 pm
STV
Member Since: 26 Feb 2023
Location: UK
Posts: 26
Thanks for this.
Not sure if my diagnostic tool will manually activate the abs solenoids or not.
I will have a go at the pressure bleed once I aquire the correct tools and update again.
Thanks meantime.
23rd Jun 2023 10:13 am
Flapper
Member Since: 04 Feb 2015
Location: Gloucester
Posts: 343
pressure bleed on onbuy is ace, makes bleeding all the brakes so easy.
Screw on the cap connect the hose fill with new fluid give it a few pumps open the bleed screw, tighten the screw move on to the next wheel after a few more pumps.
23rd Jun 2023 1:54 pm
STV
Member Since: 26 Feb 2023
Location: UK
Posts: 26
Sounds good to me 👍
23rd Jun 2023 2:17 pm
HairyFool
Member Since: 04 Jan 2023
Location: Essex
Posts: 614
Sealey VS820 Kit is £55 on Amazon, pictured on the wing of a real Defender so must be good
Curiosly exactly the same pressure bottle on a number of Chinese knockoff sellers also on Amazon.A visitor from the dark side, my other vehicle is an MG5 EV
23rd Jun 2023 5:38 pm
STV
Member Since: 26 Feb 2023
Location: UK
Posts: 26
Managed to order a replica of the sealey version off flea bay for £26.00.
I'm holding high hopes with this once it arrives so will update again once I get to this stage.
Thanks for everyone's input so far.
23rd Jun 2023 7:09 pm
STV
Member Since: 26 Feb 2023
Location: UK
Posts: 26
After purchasing my pressure bleeder and setting it up I was impressed how ridiculously easy it was to bleed the brakes on your own using one of these, so I highly recommend one.
Managed to get a little bit more air out of the lines although unfortunately my brakes are still not great.
During normal driving they appear to be ok but the most noticeable issue comes to light when doing a slow hill descent as the weight of the vehicle against gravity requires more pressure of the pedal and my brake pedal just seems to want to sink right to the bump stop with very inefficient stopping power.
I need to use my disco to pull my trailer soon but as I'm struggling to stop with only its own weight, towing is totally out of the question until I resolve this.
As I have already replaced the master cylinder, flushed out all old fluid and replaced with new dot4 and did a full system with abs pressure bleed several times. Would it be fair to say that the only issue left to fix would be my brake booster??
Don't really want to be changing this out on assumption that it is failing but I can't think what else it could be. Anybody ??
5th Jul 2023 8:11 am
Danley
Member Since: 04 Dec 2022
Location: UK
Posts: 81
Could it be a flexible hose, or something else?
Might it be worth taking it to an "MOT" place and ensuring the 4 brakes are all working ok?
5th Jul 2023 9:05 am
L319
Member Since: 14 Dec 2013
Location: Herefordshire
Posts: 2081
You say If you pump the brake pedal with the engine off it will go hard with little movement. This usually means there is no air in the system & the long travel points more to the booster issue in my limited experience. My D3 has long travel and a relatively soft pedal compared with other vehicles but the car stops well , before the pedal gets to the floor . I did change the booster for other reasons and it made a minor improvement to the soft feel.
6th Jul 2023 10:10 pm
STV
Member Since: 26 Feb 2023
Location: UK
Posts: 26
Danley wrote:
Could it be a flexible hose, or something else?
Might it be worth taking it to an "MOT" place and ensuring the 4 brakes are all working ok?
Flexible hoses appear fine with no leakage aound their fittings.
Mot will be due soon anyway so if I can't resolve it before then I'll see what mot comes up with.
7th Jul 2023 3:35 pm
STV
Member Since: 26 Feb 2023
Location: UK
Posts: 26
L319 wrote:
You say If you pump the brake pedal with the engine off it will go hard with little movement. This usually means there is no air in the system & the long travel points more to the booster issue in my limited experience. My D3 has long travel and a relatively soft pedal compared with other vehicles but the car stops well , before the pedal gets to the floor . I did change the booster for other reasons and it made a minor improvement to the soft feel.
If I thought the booster was the sure culprit I would change it out without hesitation but I'm somewhat reluctant to keep throwing new parts on and hoping for the best.
I have heard on the forums that land rover did a recall on this due to oil supposedly getting into the servo via the vacuum hose and that a modified vacuum pipe was fitted to overcome this problem.
I'm unsure if my vehicle had this recall done during previous ownership and wondered if the new modified vacuum pipe is easily identified compared to the original one fitted from factory.
7th Jul 2023 3:56 pm
DN D3 Decade
Member Since: 24 Jun 2006
Location: W.London.
Posts: 2326
I’ll see if I can find a pic of the modified pipe work for the P017 brake recall…………..Here you go….
D3 owned from new, P017 brake recall, BAS FBHIC, new FBH, LR013487 oil pump, new water pump. RRS front lower suspension arms. New suspension compressor/ relay. New Denso alternator. CuNifer rear brake pipes. New GKN rear propshaft. New HPFP belt & tensioner. New A/C Condenser.NO WARRANTY for many many years.
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