No brakes -Princes Caliper upgrade

[braveheart 3]

Happy Easter All,
Any advice as usual would be great.
Took the wedge for maiden voyage after bigg red refurb of front princess calipers and deffo more pedal travel and generally not impressed.
Ran around locally increasing in confidence and doing where safe some quicker and quicker pull ups.
They would not lock the wheels despite a lot of hefty shoves.
Disappointed and p#ssed off I went a bit further and coming up behind much slower traffic pedal went completely to the floor WTF !
Limped home in a state of shock kept pumping pedal and had about 30% brake power.
On looking after my nerves recovered the master cylinder seals on both front and back chamber are leaking badly.
So questions are gents where do i get a new one and am I missing the point with Princess calipers or is it a weak master cylinder causing the lack of bite ?
Ps pads were mintex and had been used previously on another project so no running in required etc I thought
Any advice as usual TBH wish I had left the stock set up at this rate after all the hassle but pleased I didn't do any thing stupid and take it for a fast A road blast !
Regards
Braveheart

[mrzigazaga]

Hi mate...The Princess calipers can be a swine to bleed..I think its lowest bleed nipple first..Cant remember if there are 2 or 3 on there?...If your Master cylinder is failing then you will have no or very little brakes as there is no pressure pushing the pistons.

I believe the MC is a Cortina mk4-5...

http://www.ebay.co.uk/itm/LM23600-Master-Cylinder-...

You can also get the repair kit but i would advise getting done by someone who knows what they are doing..

[pk500]

mrzigazaga said:

Hi mate...The Princess calipers can be a swine to bleed..I think its lowest bleed nipple first..Cant remember if there are 2 or 3 on there?...If your Master cylinder is failing then you will have no or very little brakes as there is no pressure pushing the pistons.

I believe the MC is a Cortina mk4-5...

http://www.ebay.co.uk/itm/LM23600-Master-Cylinder-...

You can also get the repair kit but i would advise getting done by someone who knows what they are doing..

Yes there is 3 bleed nipples and yes it helps to bleed th in the right order

[hallsie]

no matter how good or bad the rebuild is on the calipers,(from bigg red I would say excellent and have never had a problem) if the master cylinder is leaking then you will lose the brakes pretty quickly.
I changed the Taimar MC a couple of weeks ago following the symptoms you described and it sorted it completely.


Stu

[superwedge]

its aa capri one 1600 or 2000cc ,that's the one on my 89 350i, try Cortina but was wrong,

[pk500]

My master cylinder was about £45 from motor factors

[Act Daft]

Got one of these and fitted it a few weeks ago
http://brakeparts.co.uk/#!/shop/FORD/CORTINA/77-82...

All good

[tr7v8]

When they fit Princess callipers to TR7s they give a long pedal & not great braking. I upgraded to master & servo to one from a Sherpa van which is bigger & was a vast improvement. I suspect the same is true of a TVR

[adam quantrill]

Hi Braveheart,

yes it's really scary when the brakes don't work when you need them - been there, done that!

The princess calipers I expect (as has been pointed out above) will need more brake pedal, and if the master cylinder goes off as a result, then things will go from bad to worse.

The masters aren't too expensive - I think about £60 on the flea. If you find the first press is poor and then the second straight away is much better, then the master is definitely suspect.

You might want to book a slot in your MoT place and get it on the rollers rather than risk it in traffic next time ;^)

[braveheart 3]

Many thanks Gents as usual pearls of wisdom thanks again
Braveheart

[GBinUSA]

I had a brand new clutch slave cylinder knockout the master cylinder in less the a day once. The higher back pressure of the newly installed component of the hydraulic system can expose weaknesses in older seals and cause a failure at the other end. I'm going to be rebuilding my front calipers soon and I ordered a MC rebuild kit just incase.

[wild rover]

Master cylinder from a 2.8 Capri normally fits.

[SEvans]

I upgraded from the standard setup to the Princess calipers and although in theory there should be more brake travel I can't say in practice that I really noticed much difference. It certainly shouldn't be doing as you describe and does sound like either the system isn't bled properly or there is a problem with the master cylinder.
I seem to remember (it was 10 years ago) that I had to fit a loop of brake pipe to join 2 ports together on the caliper. I don't know if this is the only option or not. I have heard a few people say the setup is difficult to bleed but again I haven't noticed a problem.
When you say the pads are used, were they used on these disks? I would have thought even second hand pads would need bedding in if used on different disks or not installed exactly as they were removed.
Cheers Steve

[Sardonicus]

SEvans said:

I upgraded from the standard setup to the Princess calipers and although in theory there should be more brake travel I can't say in practice that I really noticed much difference. It certainly shouldn't be doing as you describe and does sound like either the system isn't bled properly or there is a problem with the master cylinder.
I seem to remember (it was 10 years ago) that I had to fit a loop of brake pipe to join 2 ports together on the caliper. I don't know if this is the only option or not. I have heard a few people say the setup is difficult to bleed but again I haven't noticed a problem.
When you say the pads are used, were they used on these disks? I would have thought even second hand pads would need bedding in if used on different disks or not installed exactly as they were removed.
Cheers Steve

I agree with this, when I use to do brake conversions on Ford's from Lockhead 2 pot to 4 Pot Princess calipers there was no noticeable difference with brake travel, my thoughts would be with incomplete bleeding but probably failed MC I mean we seldom stop bleeding till we have a decent pedal anyways.

[braveheart 3]

Many thanks again for the advice. Out the spanners come again !
All the best
Brave heart

[Campbell]

Hi Brave heart, how do you pressurise your system to bleed, i use one of those cheep systems that runs from a tyre on my SEAC and i find it a grate system to do these type of calipers.
For me i start with the most outer nipple and work my way back to the inside nipples.
Also excessive pumping of the pedal will could damage the master seals.
Good luck as ill be doing this some time soon.

[Furgie]

When I had princess calipers on the only way I could get all the air out was to use a bleed kit( screwfix 33881)and then they worked fine. I used the pypass pipe and one flexi pipe.