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 4th June 2024, 15:48   #1
Fred Byrne
Avid contributor
 
Rover 75 Saloon

Join Date: Jun 2018
Location: Ballynahinch
Posts: 205
Thanks: 69
Thanked 60 Times in 23 Posts
Default Brake problem; Is this mastercylinder problem

My brakes gradually got spongier and spogier. I tried to bleed them but no fluid would emerge from either the front nearside or rear offside cylinders when operating the brake pedal; with and without the engine running.. Only a dribble came out of the other two cylinders when I used a gunson brake bleeder. Is this indicative of a master cylinder problem?
I thought I might take the car to a local garage but I now have zero braking power so that solution is shelved at least temporarily.

Fred
Connoisseur 2.5 kv6
Fred Byrne is offline   Reply With Quote
Old 4th June 2024, 16:14   #2
Ched
I really should get out more.......
 
Ched's Avatar
 
MG ZT V8, MGZT 135 derv ,MG TF 135

Join Date: Dec 2011
Location: Romsey
Posts: 2,311
Thanks: 553
Thanked 573 Times in 385 Posts
Default

Hi Fred, first you need to check if you have brake fluid in the master cylinder, its located on the drivers side under the scuttle panel.
Then check the brake pipes at the rear of the car, my guess is that one of the pipes has burst due to rust, if you do have a leak check the floor for a fluid stain.
Ched is offline   Reply With Quote
Old 4th June 2024, 16:36   #3
Fred Byrne
Avid contributor
 
Rover 75 Saloon

Join Date: Jun 2018
Location: Ballynahinch
Posts: 205
Thanks: 69
Thanked 60 Times in 23 Posts
Default

The master cylinder is full and there are no leaks. The front hoses were replaced last year and I have two new ones waiting to be put on the rear. The 80 year D-Day is approaching so will have to relax until that excitement is over.
Thanks for your replay.

Fred
Fred Byrne is offline   Reply With Quote
Old 4th June 2024, 20:03   #4
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,726
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
Default

Quote:
Originally Posted by Fred Byrne View Post
... no fluid would emerge from either the front nearside or rear offside cylinders when operating the brake pedal; with and without the engine running.. Only a dribble came out of the other two cylinders when I used a gunson brake bleeder. Is this indicative of a master cylinder problem?
I would say probably yes Fred.

Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.
SD1too is offline   Reply With Quote
Old 5th June 2024, 08:47   #5
Fred Byrne
Avid contributor
 
Rover 75 Saloon

Join Date: Jun 2018
Location: Ballynahinch
Posts: 205
Thanks: 69
Thanked 60 Times in 23 Posts
Default

Thanks for that Simon. I will order a new one . It looks as though Rimmers have them at a somewhat rteasonable price.
Fred
Fred Byrne is offline   Reply With Quote
Old 6th June 2024, 05:29   #6
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,726
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
Default

Fred; I would recommend carrying out some checks before a speculative purchase such as Ched suggested:
Quote:
Originally Posted by Ched View Post
Hi Fred, first you need to check if you have brake fluid in the master cylinder, its located on the drivers side under the scuttle panel.
Then check the brake pipes at the rear of the car, my guess is that one of the pipes has burst due to rust, if you do have a leak check the floor for a fluid stain.
Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.
SD1too is offline   Reply With Quote
Old 6th June 2024, 10:25   #7
Rover600
Regular poster
 
Rover 600

Join Date: Nov 2017
Location: Norfolk
Posts: 36
Thanks: 0
Thanked 2 Times in 2 Posts
Default

I wouldn't write the master cylinder off just yet.

Some braking systems can be quite tricky to bleed, and if there is somewhere air is getting into the system then it won't bleed.
There are a lot components in a braking system and plenty of things that you can check before you start swapping parts.

You mention the hoses have been changed recently - does that correlate with any of the braking issues?
Rover600 is online now   Reply With Quote
Old 13th June 2024, 11:06   #8
Fred Byrne
Avid contributor
 
Rover 75 Saloon

Join Date: Jun 2018
Location: Ballynahinch
Posts: 205
Thanks: 69
Thanked 60 Times in 23 Posts
Default

Thank you all for the various comments. I didn't expect that removal of the master cylinder would be so difficult. It was the bottom right hand bolt on the access panel that caused the problems. I eventually removed the upper inlet manifold to gain access. I could see it but couldn't reach it!.
The problem is that the cylinder piston is not uncovering the inlet ports to the brake pipes that go to the wheel cylinders. I presume that either the rubber cups in the cylinder have swollen and are blocking off the ports or they have become dislodged in some manner. The piston will not move back any futher so it must be the seals that are blocking the ports and not allowing the wheel cylinders to re-charge..
The body of the master cylinder has Lucas 3056 stamped on it. I ordered a new cylinder from Rimmers . It is stamped Lucas 3183. It is slightly too large to slide into the servo. I think the master cylinders must have been changed at some stage during the earlier years of manufacture. i cannot find any other source for new master cylinders apart from Rimmers. I could open out the aperture in the servo (by 1.5mm ) or fit a later servo. If I knew which one!
Are there any suggestions please?

Fred



Fred
Fred Byrne is offline   Reply With Quote
Old 13th June 2024, 11:23   #9
vitesse
I really should get out more.......
 
Rover 75 Saloon

Join Date: Jul 2011
Location: Gävle
Posts: 2,583
Thanks: 395
Thanked 823 Times in 652 Posts
Default

Thankfully I've never had to play around with the brake master cylinders, seems a nightmare as these people (https://allbrit.de/xepc.cfm?PAGE=127...RRJ&SPRACHE=EN) list five of them with presumably different part numbers. You could always ask if they have one that matches yours. I did however find it useful to know there is a repair kit too.

Good luck
vitesse is offline   Reply With Quote
Old 13th June 2024, 14:59   #10
Fred Byrne
Avid contributor
 
Rover 75 Saloon

Join Date: Jun 2018
Location: Ballynahinch
Posts: 205
Thanks: 69
Thanked 60 Times in 23 Posts
Default

Thanks for tht info. I'll have to dredge up my German!!
Fred
Fred Byrne 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 18:47.


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