Brakes

[Pat]

Can anybody advise please??

I have recently replaced my calipers and rebuilt my master cylinder (morris marina), but I can't seem to get a firm pedal. Have now bled the system 5 times. . .

The brakes still feel spongey and am at wits end.

There was no scoring or damage on the internal of the cylinder, so quite sure thats not it.


Kind regards,
Pat

[MacGD016]

If you replaced the pads they may take some time to bed in.

[Pat]

Alas, no, its not the pads - those I've replaced a month ago
and had been bedded in.

Must be air in the system - some where???

Have even left the brake pedal braced down for the weekend,
and their still spongey. . . .

Any further & all advice greatfully accepted!!

Blue skies,
Pat

[dodger]

Just a thought,

Make sure your calipers are the right way up with the bleed nipples at the top otherwise you will always have air in the system.

[Pat]

Yep - right way up
Bleed nipples at the top

I have heard people mention it can be a bit of a nightmare to bleed jag brake systems. Having rebuilt the system on both a friends and my own landys with no problems, I am starting to get a little confused.

Keep'm comin.

Blue skies (maybe not so??),
Pat

[kdavies3]

Are you bleeding with a power bleed or just the old fashioned way?
I always use the old method using an assistant to pump the pump the pedal, whilst I lock off the nipples at the appropriate times.
I bled my mine about 3 or 4 times to get a really good pedal. Mine uses a Ford cylinder / servo as supplied by Dax. :thumb:

[Pat]

Have tried both & even got a mate to have a go. . . .

Still no luck.
Took apart the master cylinder again and seals are
the correct way round and in the correct order.

Aaaaaaaaaaaaahhhhhhh

Cheers,
Pat

[MacGD016]

Pat, I guess you will have tried all of these but when confused I go right to basics so for what its worth here is what I would look at:



Stationary checks:

• You say the brakes are spongy but do they pump up? I have sometimes found that I get super critical and later find that they were fine after all!
• Is there any ‘small’ sign of brake fluid round any of the unions or bleed nipples? Just the slightest dampness will mean that air is getting in
• Have you got the pads in the right way round?, I once put some pads in wrongly so that part of the metal backing was in contact with the calliper, the car stopped ok but it felt like there was air, spongy brakes!
• When you bleed them does any air come out?

Checks on the road:

• When you brake does the car pull one way; does one side lock up; does the back or front lock up? Any of these symptoms may point to where some air is in the system
• Do the brakes improve if you pump them? Defiantly suggests air, not much help except to confirm that there is air in there!
• Is there anything else different from before?

Mac

[simmo]

I had a similar problem on a dax using an mgb tandem master cylinder, no air came out when bleading the old fashioned way but couldn't get a hard pedal. Eventually found a bit of scoring which had damaged the new master cylinder seals, removed this with a bit of wet & dry then fitted new seals. Pedal still doesn't feel rock hard but brakes work spot on.
best of luck
simmo