Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > Technical Help Forum
Register FAQ Image Gallery Members List Calendar Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 17th June 2022, 19:47   #1
Olde faithful
Loves to post
 
ROVER 75 TOURER

Join Date: May 2017
Location: BIRMINGHAM GB
Posts: 355
Thanks: 27
Thanked 268 Times in 102 Posts
Default Help with a mystery

Rover 75 buddies i need some help on issue that is starting to drive me up the wall

Firstly my R75 DERV Tourer back brake pipe went, no big deal that happens so it went into the garage

when there it had new brake pipes , new caliper and bled

however on return it did this

brake pedal worked as you pressed and after two seconds started to sink to the floor, not entirely to the floor boards but sank slowly. checked and no air in the system, so the garage said it may be a seal on the master cylinder, so i said ok lets get one then so we got one and also placed three new vacuum tubes on the servo also .... wait for it

tried it again with all that done.....two seconds sank again, its not leaking and no air in the system.... so back to the drawing board, this time the garage said the T4 is not talking to the ABS system so may be its now gone as the fluid all drained out from the brake pipe going at this point i said i cannot believe a broken brake pipe would knock out the entire braking system... so in the end i said ok lets get the ABS off my donor which i knew it worked....

placed that on the car... wait for it.... same again two second brake pedal sank slowly, so now i have had brake pipes, three vacuums pipes , ABS system, master cylinder, caliper, and new fluid and brake system bled....

the garage then said the servo must be gone....i said i just cannot believe this, and said hold on lets not change this yet... the two mechs are good guys however we seem to be stumped on this.... can anyone let me know what is going on here, because i fear the worst if we change the servo again nothing will change HELP!!! ROVER 75 buddies

MY BRAKES ARE SLOWLY SINKING? ON THE FOOT BRAKE PEDDLE.
Olde faithful is offline   Reply With Quote
Old 17th June 2022, 19:58   #2
suzublu
This is my second home
 
suzublu's Avatar
 
rover 75 1.8 vvc club se wedgwood blue

Join Date: Aug 2009
Location: Seaton Carew
Posts: 26,880
Thanks: 65
Thanked 7,142 Times in 4,642 Posts
Default

Search for sinking pedal syndrome, ie https://www.the75andztclub.co.uk/for...ad.php?t=63314
suzublu is offline   Reply With Quote
Old 17th June 2022, 21:45   #3
xsport
Posted a thing or two
 
rover 75 club se

Join Date: Apr 2011
Location: Leicester
Posts: 1,600
Thanks: 358
Thanked 419 Times in 310 Posts
Default

i thought that like in the MOT quick test , pump up the brake pedal first , then hold it down and start the engine , it should fall . that is for petrol engines. you have diesel so im not sure if they have a vacuum pump system instead. Another diesel owner would know as i have never owned one. !! if the garage boys know their stuff, they would have checked for hose leakage , and that the servo is functioning or not. Its always a bad policy to just exchange parts at random for elimination. Not to mention parts and labour costs. have they run any checks on the servo ? What was their prognosis ? i would certainly ask a few more questions , before opening your wallet again. ...
xsport is offline   Reply With Quote
Old 17th June 2022, 21:53   #4
xsport
Posted a thing or two
 
rover 75 club se

Join Date: Apr 2011
Location: Leicester
Posts: 1,600
Thanks: 358
Thanked 419 Times in 310 Posts
Default

the sinking pedal syndrome is a common topic on here ,especially on automatics. mine has always done this very slightly on my auto,but never been a problem. you seem to have a floppy pedal for another reason. some say that the ABS cannot be purged of air , some say it can with T4.. ..
xsport is offline   Reply With Quote
Old 17th June 2022, 22:14   #5
Arctic
Give to Learn
 
Arctic's Avatar
 
Freelander 2

Join Date: Aug 2010
Location: West Midlands
Posts: 18,651
Thanks: 1,155
Thanked 6,407 Times in 3,874 Posts
Default

Have a read of these threads, have the garage done anything like damaging the servo?

https://www.the75andztclub.co.uk/for...d.php?t=318553

If not then look at this thread, taking notice of how Jules does his bleeding.
https://www.the75andztclub.co.uk/for...ad.php?t=63314
__________________
Arctic
Givology Learn to Give
Everything is Achievable

ad altiora tendo.

Check out our Nano meet dates
http://www.midlandsnanomeets.co.uk/

http://www.the75andztclub.co.uk/index.php?thepage=howto

" You do the work , we supply the expertise "
Arctic is offline   Reply With Quote
Old 17th June 2022, 22:19   #6
Olde faithful
Loves to post
 
ROVER 75 TOURER

Join Date: May 2017
Location: BIRMINGHAM GB
Posts: 355
Thanks: 27
Thanked 268 Times in 102 Posts
Default

Quote:
Originally Posted by Arctic View Post
Have a read of these threads, have the garage done anything like damaging the servo?

https://www.the75andztclub.co.uk/for...d.php?t=318553

If not then look at this thread, taking notice of how Jules does his bleeding.
https://www.the75andztclub.co.uk/for...ad.php?t=63314
Thanks Artic, the garage have used T4 to push the air out the ABS and the T4 shows no air however nothing has improved and the 3 vacumn pipes all been replaced and the ABS unit and the Master cylinder only the servo left and to be honest i dont think its that anyway

im stumped also on this
Olde faithful is offline   Reply With Quote
Old 17th June 2022, 22:36   #7
xsport
Posted a thing or two
 
rover 75 club se

Join Date: Apr 2011
Location: Leicester
Posts: 1,600
Thanks: 358
Thanked 419 Times in 310 Posts
Default

hi arctic. Does the diesel have its own vacuum pump system to generate the required effect ? could that not be working or not show open cicuit on T4 ?
xsport is offline   Reply With Quote
Old 17th June 2022, 23:30   #8
Arctic
Give to Learn
 
Arctic's Avatar
 
Freelander 2

Join Date: Aug 2010
Location: West Midlands
Posts: 18,651
Thanks: 1,155
Thanked 6,407 Times in 3,874 Posts
Default

Quote:
Quote:
Originally Posted by xsport View Post
hi arctic. Does the diesel have its own vacuum pump system to generate the required effect ? could that not be working or not show open cicuit on T4 ?
Hi Stefan.
The servo is connected to the EGR solenoid through the vaccum hose top one is the R40 M47 solenoid the bottom one is the Freelander 1 solenoid

1

from the solenoid
2

It joins to a one way valve, which is connected to the servo.
3

Usually if the hose as chaffed /worn through the brakes go harder but to do not go slowly to the floor.

The OP says he as changed the vaccum hoses.

You can see from these photos that the hose as worn through i found this on a local owners car, i doubt many members /owners check these hoses.
4

5

6

Something as gone wrong when the garage have changed the brake pipe on the car, either it's not been bleed correctly or they have damaged the servo?
__________________
Arctic
Givology Learn to Give
Everything is Achievable

ad altiora tendo.

Check out our Nano meet dates
http://www.midlandsnanomeets.co.uk/

http://www.the75andztclub.co.uk/index.php?thepage=howto

" You do the work , we supply the expertise "
Arctic is offline   Reply With Quote
Old 18th June 2022, 12:58   #9
Mike Noc
This is my second home
 
Mike Noc's Avatar
 
Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4.

Join Date: Jul 2009
Location: Hampshire
Posts: 11,531
Thanks: 3,470
Thanked 3,119 Times in 2,247 Posts
Default

Have the garage carried out a full brake bleed as per RAVE using the T4 with the new ABS pump installed?

If not that is the way to go.
Mike Noc is offline   Reply With Quote
Old 18th June 2022, 14:43   #10
rovermech
Regular poster
 
Rover 75 Saloon

Join Date: Nov 2006
Location: Sheffield
Posts: 54
Thanks: 1
Thanked 17 Times in 8 Posts
Smile sinking brake pedal

I am a retired mechanic with over 60 years in the trade and when ABS came along the sinking brake pedal problem seamed to get more frequent I found out when bleeding the brakes if I clamped the flex pipe & opened the bleed nipple to release the fluid when changing pads etc then remove the clamp from the brake pipe to bleed the brakes never had the problem it is the pushing the fluid back through the system that's the problem you can flip a seal in the ABS or master cyl that's my thinking anyway but what do I know I'm 84 years old
rovermech is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 16:52.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © 2006-2023, The Rover 75 & MG ZT Owners Club Ltd