KKCortina 3 Posted June 12, 2022 Guys.... have a brake bleeding issue with my '72 pre-facelift Mk3 Cortina 2000GXL.... Stripped front suspension/clip etc so disconnected all brake lines.... left brake master cylinder/servo alone with just the 2 outlet pipes unattached ......so all brake fluid in reservoir and pipes etc were drained out to empty. Connected all up again and filled reservoir with fluid in both front and rear compartment of reservoir only to discover that the fluid will not pump through brake lines when I release either one of front caliper bleed valves. I disconnected the FRONT main brake pipe feed union at bracket in front of passenger footwell (attached to chassis leg) ... i.e. the pipe that connects to short flexi that connects to brass front brake splitter. Pumped the pedal and NOTHING!..... so fluid is not making it down from the master cylinder. This has me stumped as have not touched the master cylinder internals - I just disconnected from from of servo to have a look to see if there was anything obvious..... checked that piston moved in/out freely (and it does) but couldn't see anything so fitted it back and retried........ but, alas. no luck. The master cylinder is a Girling original with part no 0168 64679155 on side .....with a small size and large size outlet so can't mix them up.....reservoir compartment nearest the servo feeds the front wheels I wish to retain this master cylinder as its the original ... so no plans to fit a Land Rover version etc.... Any ideas guys ? Quote Share this post Link to post Share on other sites
John Mack 336 Posted June 12, 2022 I'm thinking along the lines that if it's the original master cylinder and you've tried bleeding by pumping the pedal then maybe a seal has turned/split in the m/c due to the piston/seals moving past the point they've been used to going ? Replacing the seals isn't such a bad job but maybe the bore is worn/corroded? Quote Share this post Link to post Share on other sites
sheffieldcortinacentre 751 Posted June 12, 2022 Agree with John. Quote Share this post Link to post Share on other sites
KKCortina 3 Posted June 12, 2022 John/Craig..... that sounds like what happened as the pedal-pushing person said that she heard or felt a click sound at the end of first pedal push .....!!! Since I posted above, I have found a Service Kit for the Mk3 Brake Master Cylinder so that is my next course of action...... Any tips on how to open the master cylinder as the little valve thingy (coloured yellow in Pic2 above) appears to be held in place by a hex screw-in piece - any hex pieces in my socket sets are too small ...... Hate doing this job as brake fluid always spills/leaks/drains over paintwork no matter how careful you are in removing the Master Cylinder and unding the brake pipe unions as the second chamber always contains too much fluid - anyone any crafty solutions? Will update when finished... Quote Share this post Link to post Share on other sites
sheffieldcortinacentre 751 Posted June 13, 2022 Find a bolt right size lock two nuts on & use that to undo it. If ther a ridge in bore you my get away with just new seals but you'll have to vacuum or pressure bleed so the seals don't hit the ridge. Quote Share this post Link to post Share on other sites
KKCortina 3 Posted June 16, 2022 (edited) UPDATE..... (1) Removed brake master cylinder and checked over.... pistons etc seemed to be moving up and down okay - refit and refill with fluid - still the same ! (2) Removed brake master cylinder again...this time dismantled internals (came out okay and no need for air line).... bore felt fine....lucky I had a spare Brake Master Cylinder overhaul kit......fitted..... tried to bleed again....again nothing! (3) Checked each brake pipe/flexi pipe union - and there are many on a Mk3 Cortina!...... fluid flow traced down to 2-way front brass splitter...... then removed flexi pipe on LH side and cleaned it up and checked whether air/fluid could pass through..... BLOCKED! Yes...at last a breakthrough...... replaced both front flexi pipes and bled front brakes this morning - brakes work but pedal not great as - I think - the rear ones (on a separate line) need to be bled when I get access to same when front wheels are replaced and car can move forward in garage. How did it happen that both flexi pipes were blocked ? Not sure but I cleaned up the rusty/stained flexi's x 2 on a rotary wire wheel....... the heat generated must have closed access to each union.When I cut open the old blocked flexi I discovered that the actual fluid passageway is tiny - never knew this! It would take very very little to block them! As they say "Every day's a school day"! Again ...thanks to Craig and John Mack for replies and suggestions - good one Craig regarding the bolt and two nuts trick..... eventhough the hex was a 0.5 inch imperial fitting in a Girling master cylinder, I purchased a 12mm hex key from a local motor factor and wound some masking tape around it to bring it up to a 0.5" equivalent metric fit of 12.7mm - it worked! But neat fix/trick all the same! I ordered a full set of hex keys - both imperial and metric - from Amazon on Monday - delivered lunchtime today - won't be caught out again! Edited June 16, 2022 by KKCortina Quote Share this post Link to post Share on other sites
GhiaMk4/5 207 Posted June 19, 2022 My rear brake pipe failed and for the life of me, could not get the brakes to work, in the end, I bled opposite side front caliper and then went around the car again and finally got a good pedal again, as above, never too old to learn. Quote Share this post Link to post Share on other sites
KKCortina 3 Posted June 19, 2022 Agreed... what sequence did you use.... was it Left Front...then Right Front....and lastly the single Rear one (on right side??...or is it Left side???)...... Quote Share this post Link to post Share on other sites
KKCortina 3 Posted July 1, 2022 Guys - still in trouble with getting a good brake pedal with this GXL.... getting impatient now! I have replaced front brake flexi's as above..... and still cant get a consistent good pedal..... I am now back to the Master Cylinder where I think the real problem is despite having replaced all the rubber seals as per above pic of master cylinder internals! I even got a Gunson Brake Bleeding Kit (the one that works using a spare tyre to pressurise the master cylinder) .... when I tested the kit under pressure with no fluid in the bottle some brake fluid appeared to leak from under where it joins the servo (2 x nuts) .... and also a leak from where the front of reservoir pushes down into master cylinder. I stopped this leak at front of brake reservoir by using a cable tie tightened to the last to keep the reservoir tight against the master cylinder body..... Despite being aware from other threads that it would be difficult to remove the reservoir body (front push-in section) it came out with only a few left/right twists. Using the Gunson kit did not solve my problems ....so it has to be the master cylinder seals or bore. The bore looks okay and the piston came out very easy without using air pressure. HOWEVER..... I noticed one possible area to investigate and query...when I pump the brake pedal (which goes to the floor) there are very large air bubbles surfacing in the front section of the section of of reservoir - in other words ...every push action of the brake pedal and master cylinder piston is pushing large air bubbles up through the front reservoir compartment ..... this can't be right and brings into question have I fitted a seal incorrectly .... A few queries... 1) What type of seal goes into this front push-in opening in the m/cyl..... I have fitted a new small circular seal and the front reservoir push-in plug/thingy just seems to sit on this seal ....or should it push up on the plastic plug-in part...... all that appears to keep this push-in piece sealed is to tighten the 2 x screws at the other end of the reservoir/master cyl. 2) Is there a seal between the m/cyl and the face of the brake servo (nothing on mine - only used blue gasket paste to seal) If I cannot make progress on above, I will have to send to Past Parts or similar to get professional help!! Forgive the long-winded commentary below but I am getting desperate Quote Share this post Link to post Share on other sites
sheffieldcortinacentre 751 Posted July 1, 2022 I know you don't want to here this but you need a new master cyl. Quote Share this post Link to post Share on other sites
KKCortina 3 Posted July 2, 2022 No problem hearing the best advice! Any idea where to get a genuine Mk3 Cortina (with Servo) one Craig? Most people talk about a specific Land Rover version .... any idea of model no. and whether you need to change the 2 union fittings (11mm and 13mm??) to imperial ? Quote Share this post Link to post Share on other sites
sheffieldcortinacentre 751 Posted July 2, 2022 It's the Landrover 90 83-90ish only needs the 13 mm swapping to 11mm have them on 2 of mine. £40-50. Dunno re a MK3 one just a case of shopping round but there silly money £100+. Quote Share this post Link to post Share on other sites
KKCortina 3 Posted July 3, 2022 Thanks Craig.... are you saying that the 2 unions on the Land Rover unit are Metric nad NOT Imperial?........so 2 x 11mm rather than the 11mm and the 13mm currently on the GXL Mk3 Cortina?...... thought all LR's were imperial ... Quote Share this post Link to post Share on other sites
sheffieldcortinacentre 751 Posted July 3, 2022 Both are same size/thread as smaller cortina union. Leandrover master cylinder bolts straight on you only have to swap the larger union for a small one. Quote Share this post Link to post Share on other sites
KKCortina 3 Posted July 4, 2022 Thanks Craig.... what would BSC do without your ever-present presence and advice - always a guaranteed response ....KK Quote Share this post Link to post Share on other sites
