Brake problem; Is this mastercylinder problem

Fred Byrne · 4th June 2024, 15:48

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

Ched · 4th June 2024, 16:14

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.

Fred Byrne · 4th June 2024, 16:36

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

SD1too · 4th June 2024, 20:03

Quote:

Originally Posted by Fred Byrne

... 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

Fred Byrne · 5th June 2024, 08:47

Thanks for that Simon. I will order a new one . It looks as though Rimmers have them at a somewhat rteasonable price.
Fred

SD1too · 6th June 2024, 05:29

Fred; I would recommend carrying out some checks before a speculative purchase such as Ched suggested:

Quote:

Originally Posted by Ched

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

Rover600 · 6th June 2024, 10:25

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?

Fred Byrne · 13th June 2024, 11:06

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

vitesse · 13th June 2024, 11:23

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

Fred Byrne · 13th June 2024, 14:59

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

4th June 2024, 15:48	#1
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 202 Thanks: 69 Thanked 60 Times in 23 Posts	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

4th June 2024, 16:14	#2
Ched I really should get out more....... MG ZT V8, MGZT 135 derv ,MG TF 135 Join Date: Dec 2011 Location: Romsey Posts: 2,308 Thanks: 553 Thanked 573 Times in 385 Posts	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.

4th June 2024, 16:36	#3
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 202 Thanks: 69 Thanked 60 Times in 23 Posts	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

5th June 2024, 08:47	#5
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 202 Thanks: 69 Thanked 60 Times in 23 Posts	Thanks for that Simon. I will order a new one . It looks as though Rimmers have them at a somewhat rteasonable price. Fred

6th June 2024, 10:25	#7
Rover600 Newbie Rover 600 Join Date: Nov 2017 Location: Norfolk Posts: 29 Thanks: 0 Thanked 2 Times in 2 Posts	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?

13th June 2024, 11:06	#8
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 202 Thanks: 69 Thanked 60 Times in 23 Posts	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

13th June 2024, 11:23	#9
vitesse I really should get out more....... Rover 75 Saloon Join Date: Jul 2011 Location: Gävle Posts: 2,576 Thanks: 395 Thanked 823 Times in 652 Posts	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

13th June 2024, 14:59	#10
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 202 Thanks: 69 Thanked 60 Times in 23 Posts	Thanks for tht info. I'll have to dredge up my German!! Fred