PV brake master cylinder

arcturus · Nov 19th, 2018, 10:37

How do I diagnose a failing master cylinder, what are the signs?

CLIVERALLY · Nov 19th, 2018, 14:43

Ok...having to pump the brake to get it to do anything....also look up at the pedals on the inside of the car, you may also see fluid on the bulkhead near the cylinder.. you may see fluid. You may also experience the pedal sinking to the floor

arcturus · Nov 19th, 2018, 14:58

I don't need to pump but I get a "sponginess" not a firm solid feel. Problem is that I know that PV drum brakes are not the best but I have no other PVs here to compare. Just fitted a new wheel brake cylinder and bled the brakes. Don't get a crisp "stop" Wondered if the master cylinder seals were worn or perhaps a worn cylinder

CLIVERALLY · Nov 19th, 2018, 16:18

If the brakes are spongy and you have bled them fully , non of the flexis bulge under full pedal pressure and car running..then without looking at it you could have a master cylinder issue..the pedal would in extreme circumstances sink to the floor. The danger here is that if you have a servo then this too can give you an insecure feel when applying the brakes...best and simplist trick for the servo is to pump the brake until it's hard and start the car...if the pedal does not move or it continues to travel to the floor after initial give then the servo is stuffed.

old fart · Nov 19th, 2018, 16:18

Was the pedal spongy before you changed the wheel cylinder? If not, you probably need to bleed some more.

arcturus · Nov 19th, 2018, 16:32

Whenever I apply the brakes a little voice comes from behind the dash and says, "do you really want me to stop"

Army · Nov 19th, 2018, 17:45

There's nothing much to go wrong with them - if you're having trouble bleeding try draining some fluid out and then use a pressure bleeder to push fluid back up through the system from each bleed nipple.

Nov 19th, 2018, 10:37	#1
arcturus arcturus Last Online: Today 07:16 Join Date: Mar 2006 Location: Sagres Portugal	PV brake master cylinder How do I diagnose a failing master cylinder, what are the signs? __________________ life's too short to drink bad wine

Nov 19th, 2018, 14:43	#2
CLIVERALLY Master Member Last Online: Apr 18th, 2024 23:55 Join Date: May 2010 Location: wetherby	Ok...having to pump the brake to get it to do anything....also look up at the pedals on the inside of the car, you may also see fluid on the bulkhead near the cylinder.. you may see fluid. You may also experience the pedal sinking to the floor __________________ Clive "Lets turn up the juice and see what shakes loose" Last edited by CLIVERALLY; Nov 19th, 2018 at 14:49.

Nov 19th, 2018, 14:58	#3
arcturus arcturus Last Online: Today 07:16 Join Date: Mar 2006 Location: Sagres Portugal	I don't need to pump but I get a "sponginess" not a firm solid feel. Problem is that I know that PV drum brakes are not the best but I have no other PVs here to compare. Just fitted a new wheel brake cylinder and bled the brakes. Don't get a crisp "stop" Wondered if the master cylinder seals were worn or perhaps a worn cylinder __________________ life's too short to drink bad wine

Nov 19th, 2018, 16:18	#4
CLIVERALLY Master Member Last Online: Apr 18th, 2024 23:55 Join Date: May 2010 Location: wetherby	If the brakes are spongy and you have bled them fully , non of the flexis bulge under full pedal pressure and car running..then without looking at it you could have a master cylinder issue..the pedal would in extreme circumstances sink to the floor. The danger here is that if you have a servo then this too can give you an insecure feel when applying the brakes...best and simplist trick for the servo is to pump the brake until it's hard and start the car...if the pedal does not move or it continues to travel to the floor after initial give then the servo is stuffed. __________________ Clive "Lets turn up the juice and see what shakes loose"

Nov 19th, 2018, 16:32	#6
arcturus arcturus Last Online: Today 07:16 Join Date: Mar 2006 Location: Sagres Portugal	Whenever I apply the brakes a little voice comes from behind the dash and says, "do you really want me to stop" __________________ life's too short to drink bad wine

Nov 19th, 2018, 16:18	#5
old fart Master Member Last Online: Mar 28th, 2024 14:15 Join Date: Apr 2012 Location: Droitwich	Was the pedal spongy before you changed the wheel cylinder? If not, you probably need to bleed some more.

Nov 19th, 2018, 17:45	#7
Army marches on his stomach Last Online: Feb 11th, 2022 03:15 Join Date: Jan 2018 Location: Somewhere in the Netherlands	There's nothing much to go wrong with them - if you're having trouble bleeding try draining some fluid out and then use a pressure bleeder to push fluid back up through the system from each bleed nipple. __________________ 1961 Volvo PV544 the quick and easy in between project(!) 1981 Mercedes 300D <=> 230 diesel to petrol conversion project 1965 Series 2a Station Wagon mega build 1992 Mercedes 190E The car that works!

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)