fullfatrr.com - View topic - Brake pedal sinks to floor

Advertise on fullfatrr.com »

Forum · Gallery · Wiki · Shop · Sponsors

Home · FAQ · New Posts · My Posts · PMs · Search · Members · Map · Calendar · Profile · Donate · Register · Log In

Home > Technical (L322) > Brake pedal sinks to floor

Page 3 of 3

Print this entire topic ·

JayGee

Member Since: 27 Jul 2021
Location: London
Posts: 3249

2012 Range Rover Vogue 4.4 V8 Orkney Grey

Glad it's sorted - was the bleeding procedure the ABS purge procedure or just a normal brake fluid bleed? 2012 TDV8 Vogue (L322)

15th Aug 2024 8:15am

kevinp

Member Since: 28 Sep 2019
Location: Telford
Posts: 1217

2011 Range Rover Autobiography TDV8 Santorini Black

I don't know what the master cylinder seal looks like but is it possible that it could have 'flipped' the wrong way hence the peddle creep and then when you pulled the piston out it could have flipped the correct way therefore explaining why it's mysteriously resolved it's self, if that makes sense?

15th Aug 2024 10:35am

kevinp

Member Since: 28 Sep 2019
Location: Telford
Posts: 1217

Goin to give this pressure bleeder a go.

It also has a twin caliper bleeder attatchment.

Click image to enlarge

15th Aug 2024 1:04pm

Pawl

Member Since: 07 Nov 2017
Location: West Midlands
Posts: 693

Ian_D wrote:
Hi All, Bit of an update!

I managed to remove the master cylinder today (at last!).

........

Plugged in the laptop and ran through the bleeding process in SDD. Now the brakes feel like they should. Firm, with no sinking at all. So, I’ve no idea what the issue was, or what I’ve done really… but it all seems fine (for now at least!).
Ian

Well done on a positive result !

It's possible that there may have been a tiny bit of debris stuck on the lip of 1 of the main pressure generating seals - enough to cause a small amount of fluid to escape very slowly around the debris & resulting in a slow loss of pressure / pedal creep. You could have dislodged it while removing / cleaning the internals.

We used to investigate faulty mastercylinders - with the failure description "pedal went to floor" where I worked & often by the time we investigated they would test as "good" & we couldn't find an internal fault.
Sometimes you can dislodge debris on seal lips during the bleed process - especially a pressure bleed - as you can force fluid over the seal lips "cleaning off" small particles.
You can cause a similar effect sometimes by applying the brake, then pulling the brake pedal back fast. Paul,
2001 Discovery 2 TD5, 211,000 miles & climbing
2006 FFRR TDV8 Vogue 151,000 miles & now sold
Member of Midland (Land) Rover Owners Club, www.mroc.co.uk

15th Aug 2024 1:38pm

JayGee

Member Since: 27 Jul 2021
Location: London
Posts: 3249

Quote:
You can cause a similar effect sometimes by applying the brake, then pulling the brake pedal back fast.

Just tried this but no change. I can push the pedal down with my hand so it's not requiring much force. Also tried an emergency stop from 50mph and >2.5 tonnes decelerated so fast I thought the laws of physics suddenly stopped applying. 2012 TDV8 Vogue (L322)

15th Aug 2024 4:39pm

kevinp

Member Since: 28 Sep 2019
Location: Telford
Posts: 1217

Just an update on my previous post up above.
I've used the pictured pressure bleeder and it's made a tremendous difference. The brake pedal is now solid and works right at the top of it's travel.
It has the smallest of pedal creep and then goes solid.
I didn't use the IID tool but instructions say to bleed the inner caliper nipple on the front first when you get to the front brakes.
I had all the symptoms of the above posts so there is a chance that other cars might not need expensive replacement parts.
I used about 2 litres of fluid and can honestly say there was no air bubbles during any of the bleeding.
Hope this helps.

29th Aug 2024 8:56am

JayGee

Member Since: 27 Jul 2021
Location: London
Posts: 3249

Great news! - Do the brakes feel more effective in a hard stop or is it just the pedal feel and was it a 1 person operation or does it need another pair of hands? 2012 TDV8 Vogue (L322)

29th Aug 2024 9:19am

kevinp

Member Since: 28 Sep 2019
Location: Telford
Posts: 1217

The brakes worked fine before but the pedal travel was long, sometimes needing a double press to get the pedal back near the top.
Easy One man operation mate.

29th Aug 2024 10:25am

JayGee

Member Since: 27 Jul 2021
Location: London
Posts: 3249

Don't have a compressor...... 2012 TDV8 Vogue (L322)

29th Aug 2024 11:56am

Page 3 of 3

All times are GMT

Jump to

< Previous Topic | Next Topic >

Posting Rules

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum