fullfatrr.com - View topic - Brakes: excessive travel and sponginess

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 > Maintenance & Mods (L322) > Brakes: excessive travel and sponginess - any advice please?

Page 1 of 1

Print this entire topic ·

MarcoPolo

Member Since: 07 Dec 2018
Location: Preston
Posts: 19

2003 Range Rover Vogue 4.4 V8 Baltic Blue

Brakes: excessive travel and sponginess - any advice please?

I’d really appreciate any thoughts other members might have. I don’t know if there’s actually a problem with my vehicle’s brakes or whether I’m chasing a ghost. I’ve studied various threads on this very helpful forum, many of which were most useful, but I’m still at a loss. Please let me explain.

The vehicle is a 2003 L322 Vogue with 4.4L V8 BMW petrol engine. It passed its MOT last December with two advisories: bushes of the upper and lower front suspension arms beginning to wear. I decided to have the arms on both sides replaced, reasoning that if one side is going the other side isn’t far behind. I purchased the parts and had them fitted by the qualified, highly experienced mechanic I’ve used for years.

Immediately after the job was completed there was a problem with the brakes (which were fine before the suspension components were changed) in that there was excessive pedal travel (the pedal would easily sink all the way to the bottom) and there wasn’t much braking power. I had to stand on the brakes to make the vehicle stop. Both the mechanic and I were flummoxed because the brakes hadn’t been touched during the suspension job - not even the wheels were taken off.

All the brake callipers, discs, pads etc. had been replaced two years ago with new units, as were a number of brake pipes, and there were no signs of any brake fluid leaks. So, the mechanic suspected lack of vacuum and measured it at the servo entry point. As you can see from the photo, it was about 18 inches of mercury (60 Kilopascals) i.e. just inside the green zone.

I understand it should be between 18 and 22 inches so it was just in spec. The mechanic believed it was too low and suspected a problem with the vacuum non-return valve (part number LKN000020 - see photo) so we replaced this with a genuine LR part. The vacuum then increased to about 25 inches of mercury – a significant improvement.

Although the brakes were more effective, there was still excessive travel and sponginess - I could still depress the pedal to the bottom. After further investigation the mechanic noticed a slight hissing noise from the servo suggesting a perforated diaphragm, so we replaced it with a new OEM unit (TRW) necessitating bleeding the brakes which the mechanic did on all four wheels several times. All this improved the brakes to the extent that the ABS could be made to kick in with an emergency stop. However, the pedal was still very spongy and I could still gradually push it to the bottom just by maintaining moderate pressure on the pedal with the engine running and vehicle stationary.

The only other original components in the system were the ABS block, master cylinder and a few brake pipes. We’d proved the ABS was working so, after researching threads on this forum for guidance, decided to try replacing the master cylinder. We replaced it with a new OEM unit (TRW) and once again bled the entire braking system to within an inch of its life. This resulted in a marginal improvement of brake performance in that the brakes start to bite as soon as I begin depressing the pedal, but the pedal is still very spongy and I can still depress it to the bottom by maintaining moderate pressure on the pedal. With the engine off, if I purge the servo the pedal becomes rock hard as expected.

In summary, almost the entire braking system has now been replaced with the exception of the ABS block (which works ok) and a few brake pipes. However, the brakes just don’t feel right and I’m especially concerned that I can sink the pedal to the floor with constant moderate pressure (something I cannot do in my Defender, the brake pedal of which is much firmer). I’m still troubled that the brakes were fine until I had the suspension components changed – I’m suspicious of coincidences.

Can anyone point me to any other cause of this, or is it ‘normal’ for a V8 Vogue and I’m chasing a non-existent problem? Any ideas would be very much appreciated. Many thanks in advance.

19th Mar 2021 4:35pm

Haylands

Member Since: 04 Mar 2014
Location: East Yorkshire
Posts: 7908

2014 Range Rover Autobiography SDV8 Loire Blue

My old 2002 would let you press the pedal to the floor if you sit with moderate pressure on the pedal, it was like it the entire time I owned it but did not effect the breaking at all... I think they are just like that..!!

The sponginess could be a sticking calliper, I had it when one of the front callipers seized up, I know you said you got the ABS to cut in so maybe it is a sticking rear one...

Worth checking them all as it's free and you never know.. Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

19th Mar 2021 7:40pm

MarcoPolo

Member Since: 07 Dec 2018
Location: Preston
Posts: 19

Many thanks Pete. That's very helpful, and it's good to know that there is/was at least one other like mine! The mechanic suggested that because the vacuum had been significantly increased by replacing the non-return valve, the brakes would have a very different feel to them, which in light of your own experiences seems reasonable. I'll also check out the callipers as you suggested. Thank you again. MP

19th Mar 2021 7:51pm

LROMAD

Member Since: 10 Oct 2015
Location: Cheshire
Posts: 54

2008 Range Rover Vogue TDV8 Stornoway Grey

Hi Marco ,did you resolve your problem with your brakes? I'm having very similar symptoms,with my 2008 tdv8.Any information would be v helpful. Thanks ,LROMAD

7th Jun 2021 10:30am

Swipe

Member Since: 31 Aug 2018
Location: Rustington, West Sussex
Posts: 99

2004 Range Rover Autobiography Td6 Java Black

I’ve just replaced my front disc, pads, calipers and bleed the brakes, before the brakes took a little bit of travel before they felt like they would apply.
Now I harding touch the pedal and it feels like it’s applying. Probably helped having fresh fluid as I’m not sure when it was last changed. 2004 Autobiography TD6 Java Black

7th Jun 2021 4:39pm

AJGalaxy2012

Member Since: 11 Jun 2018
Location: Gainsborough
Posts: 1459

2012 Range Rover Vogue SE 4.4 V8 Bonatti Grey

Haylands wrote:
My old 2002 would let you press the pedal to the floor if you sit with moderate pressure on the pedal, it was like it the entire time I owned it but did not effect the breaking at all... I think they are just like that..!!

Thats leaking master cylinder seals that causes that and you should be thankful you never did long descents requiring braking for an extended time with moderate pressure. It would definately had an effect on braking performance then

BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

7th Jun 2021 5:03pm

AJGalaxy2012

Member Since: 11 Jun 2018
Location: Gainsborough
Posts: 1459

MarcoPolo wrote:
Many thanks Pete. That's very helpful, and it's good to know that there is/was at least one other like mine! The mechanic suggested that because the vacuum had been significantly increased by replacing the non-return valve, the brakes would have a very different feel to them, which in light of your own experiences seems reasonable. I'll also check out the callipers as you suggested. Thank you again. MP

There would be a different feel is so much that little pedal pressure is needed to achive good braking performance, if the pedal pressure is the same but the travel is excessive, try clamping the flexible hoses in turn until you find one that reduces the pedal travel, you then found the guilty party that needs more bleeding, or bleed some more using a pressure bleed device. Pedal travel = air in the system or fluid going somewhere. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

7th Jun 2021 5:06pm

Page 1 of 1

All times are GMT + 1 Hour

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