MODIFIED BRAKE MASTER CYLINDER

Post by **ronwilson** » Wed Feb 23, 2005 11:32 pm

HI- HAVE LOOKED BUT NOT FOUND ANY RECENT POSTINGS ON THIS ASPECT. SOMETIME BACK FITTED MARINA FRONT DISC BRAKES AND MODIFIED THE O/E LOCKHEED BRAKE CYLINDER(AS INSTRUCTED) BY REMOVING THE VALVE CAP TO BACK-OFF SYSTEM PRESSURE ON THE DISCS. RAN CAR SEVERAL YEARS WITHOUT PROBLEMS. HAVE NOW ADDED REAR DISC BRAKES AND A REMOTE RESERVOIR-DID THE USUAL BLEEDING SEQUENCE. NOW WITH BRAKE PETAL DEPRESSED FOR SEVERAL MINUTES, THE PRESSURE SLOWLY RELEASES. RECKON THE FLUID IS ESCAPING PAST THE PISTON. IN FITTING A NEW SEAL KIT, FOUND STEEL DISHED WASHER HAD SOME SMALL DENTS NEAR EDGE BUT NO REPLACEMENT SUPPLIED. TRIED A DELPHI LOCKHEED M/C BUT THREADS AND INTERNAL COMPONENTS ARE DIFFERENT. ANYONE MEET SIMILAR PROBLEM WITH DISCS ? ANY SOURCES FOR A NEW DISHED WASHER ?

Post by **jonathon** » Thu Feb 24, 2005 8:01 am

The common problem with fitting front and rear discs is that the M/C capacity may be insufficient. You need to find the capacity of all brake cylinders and see if the total is less than the M/C. If it is, then you will have only one or two stabs on the pedal before it goes spongy then loose brakes to a dangerous level. You can fit the Series11 M/C which has a larger capaciy. We are working on a stainless lined overbored M/C to eleviate this potential problem.

Post by **rayofleamington** » Thu Feb 24, 2005 9:54 am

BY REMOVING THE VALVE CAP TO BACK-OFF SYSTEM PRESSURE ON THE DISCS.

That won't affect your pressure loss problem as it is (was) only active when you let go of the brake pedal.
If you hold the pedal and it goes soft in a few minutes then you either have an internal leak at the primary in the m/c or an external leak in the pipes/cylinders (I doubt is is an ecxternal leak as you seem to know what you're doing and therefore would have looked for that first ;-) )

As for the non-standard Delphi 'Lockheed' m/c... I've been telling people for ages that although it may come from the original casting it is not the original part, but most people think they are buying an 'original part'.
Delphi-distribution bought the rights to use the AP logos (eg. Lockheed) so they can put anything they want in a Lockheed box. The factory where the original AP Lockheed parts were made was raised to the ground some time ago, but anyway the parts had not been made there for a long time.

Post by **ronwilson** » Thu Feb 24, 2005 11:26 am

[quote="jonathon"]The common problem with fitting front and rear discs is that the M/C capacity may be insufficient. You need to find the capacity of all brake cylinders and see if the total is less than the M/C.

THANKS JONATHAN,
WE INCREASED THE FLUID CAPACITY OF THE 1098cc M/C WITH A REMOTE RESERVOIR BUT THAT HASN'T AFFECTED THIS PROBLEM. BELIEVE M/C LETS FLUID GET PAST THE PISTON & SEALS WITH THE PEDAL DEPRESSED BECAUSE OF FAULTY DISHED WASHER. ANY LEADS FOR A REPLACEMENT WASHER ?

RAY, BOUGHT THIS NO LOGO M/C FROM A NORFOLK CLUB SUPPLIER IN GOOD FAITH BUT AS SAID ITS DIFFERENT. HAD IT MODIFIED TO TAKE FITTINGS FOR THE REMOTE RESERVOIR & STILL WORKING IT. VERY TEDIOUS PROCESS ! IS RECONDITIONED O/E A POSSIBILITY ? ANY THOUGHTS ? THANKS.

Post by **rayofleamington** » Thu Feb 24, 2005 12:02 pm

IS RECONDITIONED O/E A POSSIBILITY ? ANY THOUGHTS ? THANKS.

The biggest problem with the O/E is that you get corrosion in the bore around the secondary seal - Hopefully someone will start selling recon O/E ones with a stainless liner - that would be the best thing to go for, but at present not available off the shelf.

Post by **custommartin** » Thu Feb 24, 2005 6:04 pm

jonathon wrote: You can fit the Series11 M/C which has a larger capaciy.

..............if you can find one - they are a bit like rocking horse droppings!

I have put a wanted ad on this site before without success.

I have discs all round and am thinking of fitting another pedal assembly/master cylinder set up as you cannot take chances with brakes!

Post by **jonathon** » Thu Feb 24, 2005 8:07 pm

Fitting a header tank is not the same as making sure that the M/C has enough displacement. There are also two ways to modify the M/C , either full removal of the bonded cup seal or drilling a 1/16" hole in the seal, easier said than done!. The latter mod allows residual back pressure of the desired rate, full removal can lead to difficult bleeding as too much fluid is allowed back. We currently have stocks of about 30 M/C ready for overbore to Series 11 spec with a stainless liner. These will be marketed soon if there is enough interest. If there are those of you who require even greater capacity, let me know and we'll try and find a suitable seal kit.

Post by **custommartin** » Fri Feb 25, 2005 6:09 pm

jonathon wrote: We currently have stocks of about 30 M/C ready for overbore to Series 11 spec with a stainless liner. These will be marketed soon if there is enough interest.

I'm about to start building a new chassis, so things (brakes etc.) may change from standard, but I would certainly be interested.

Post by **ronwilson** » Sat Feb 26, 2005 12:09 pm

jonathon wrote: We currently have stocks of about 30 M/C ready for overbore to Series 11 spec with a stainless liner. These will be marketed soon if there is enough interest.

Jonathon,
We're still working the problems with our two 13/16 M/C's. If "push comes to shove" ie we don't get one of them working we'd be interested in trying out your overbore to SeriesII spec with stainless liner. Will come back to you on that. First, what kind of internals-piston and seals do you envision using with this overbore ?

Post by **jonathon** » Sun Feb 27, 2005 10:19 am

Details of seals etc are closely guarded at the moment I'm afraid, for obvious reasons. All will be revealled soon

Post by **ronwilson** » Tue Mar 01, 2005 7:53 pm

Thanks everyone for your inputs. Still looking for the DISHED WASHER to replace ours in a 13/16 M/C in a 1098cc Traveller. Any help there much appreciated.

Post by **ronwilson** » Thu Jun 02, 2005 4:49 pm

Hi all,
It's now start of June and hard to believe that our braking problem hasn't yet been resolved. Have replaced seals on the 13/16 m/c and bled the system so many times (gravity and pressurised back bleed) that we've lost count ! Rerouted the piping system from over the gearbox back to its original position across the front chassis member but still getting air into the system from somewhere. Have begun isolating (blanking off) parts of the system-front vs back and now about to try right front vs left front with an exterior mounted Girling m/c. Still unable to get pedal pressure on first depression; comes well after 2 - 3 pumps but that won't pass MOT. Maybe Jonathon's comments about the m/c not up to needed capacity & his warning about rigid to flexi unions can leak & let in air are right. Will now start looking for relief in that direction.

Post by **ronwilson** » Thu Jun 02, 2005 4:52 pm

Oops ! Forgot to mention that we obtained a dished washer to replace our damaged one from ESM. It obviously wasn't the whole answer.

Post by **bmcecosse** » Thu Jun 02, 2005 8:11 pm

I can't imagine why you would want rear disc brakes - unless it's a race car ? Seems to me the trouble far outweighs any possible advantage. The rear brakes on a road car do almost nothing !

Post by **ronwilson** » Thu Sep 08, 2005 12:21 am

bmcecosse wrote:I can't imagine why you would want rear disc brakes - unless it's a race car ? Seems to me the trouble far outweighs any possible advantage. The rear brakes on a road car do almost nothing !

I'm sure you're technically correct. We've customised our Moggie with a Fiat TC and I've always liked the idea of discs all round. It's been up and running since early August-goes well, stops well and we're well pleased with its running in. Still some refining to do but the interior finished in late August and looks a treat. Thanks all for your interest and comments over this extended period.

Post by **Blunt** » Thu Sep 08, 2005 12:35 am

well done Ron

I must admit I can't see the point of rear discs...

but, hey...whatever floats your boat

btw...I'm glad you've stopped shouting