Lancia Motor Club

I I decided a while back to put new brake fluid in the car as the existing fluid has been sitting there for at least five years.  Unfortunately I walked into a can of worms.

The front bleed nipples wouldn’t budge initially, but with a few days soak in WD40 they came free and I’ve replaced them with new ones.

At the rear I was puzzled to find no bleed nipples, just solid Allen key grub screws.  They were M8 and coarser thread rather than the correct M7.  I managed to find some nipples of the correct specification, but they wouldn’t screw in which led me to believe the ends of the original nipples were probably still seized in place.  Seems a previous owner  had drilled out part of the seized nipples and enlarged the accessible part of the thread to allow a grub screw to be fitted.  So the car had no bleed capability at the rear!  

I took the calipers to Classicar Automotive in Cheshire and they did a lovely job repairing and refurbishing them.  They removed the seized nipple portions and fitted ball bearings to seal the fluid entry, and put a concave surface on M8 bleed nipples to mate with the ball bearings.

I fitted the new calipers and tried today to bleed the system.  I used the old fashioned manual system, with my wife pressing the brake pedal when I shouted,  and releasing it on a subsequent call. I read the dozen or so forum threads on this topic and decided to keep things simple, especially as I was starting with a filled system, rather than one that had been drained.  I started furthest away from the master cylinder, with the back of the car jacked up by the axle.  Both rears seemed to bleed alright.  

Then I started on the front left.  The lower nipple bled as I would have expected, but when I loosened the top nipple I had no fluid flow. I checked that the nipple passageway was clear, and I checked that fluid flowed freely when the nipple was removed.  So I was puzzled as to why I would not get the normal stream of fluid when the brake pedal was depressed with the bleed nipple opened.

I then moved to the  front right, and my experience was exactly the same as with the left.  The bottom nipple seemed to bleed correctly, but no fluid flow from the top nipple.

Does anybody have any suggestions as to what might be happening.  One person has suggested that front top nipple and and rear nipple on one side of the car should be bled simultaneously, but I’ll need a third person to try that.

Hi Norm, I'd say shout if you need another pair of hands (or feet) but at the moment I'm not free due to family issues.

Have you tried bleeding the front circuits without the upper bleed nipples in at all? If you get fluid out it must be blocked nipples? Can you blow through the nipples?

Guy

And not being familiar with Fulvia callipers... Should they have bleed nipples top and bottom on a single piston brake? If not then I'd suggest that you've got the callipers on the wrong sides? Swap them over and the nipples that you can bleed will be at the top?

Guy

According to Lancia instructions, on S2 cars the first nipple to be bled is the top one on the passenger side, then the other top one, then the lower ones etc. You might need a suction pump to get the flow now, Andrea

Hi Guy - the nipples are brand new each side and are not blocked.  The Fulvia has twin pot brakes, hence two nipples each side.

Andrea - fluid flows freely when the top nipples are removed so I don't have an air blockage.   I'm trying to figure out why pressing the pedal doesn't result in fluid flow. 

Could it be that the second pump in the master cylinder is not working? Is it that second pump that feeds the top front pistons?

Are the flexible hoses new, could they be collapsed or blocked the inside?

The hoses and pipes look fine Neil, and fluid flows when the top nipples are removed so there are no blockages.

I'm still suspecting that the master cylinder second circuit is not pumping but not sure how to confirm it.  I'm hoping someone on the forum has encountered a similar situation and can advise.

Perhaps check for pressure at the m/c outlet?

Norm, I think there might be a problem with the front piston in the master cylinderb as this is the one feeding the flow system for the top nipple circuit. Slacken (don't remove it) the front tube connection at the master cylinder and try to see if there is fliud coming out when pressing the pedal. Andrea

Thank you Richard and Andrea - I'll do as you both suggest and see if I've got fluid flow from the m/c front outlet. I'll track the plumbing to see which pipes feed the front top caliper nipples.   The nuts holding the outlet pipes won't budge at the moment so I'll give them a good soak in WD40 for a few days and then try again.

Also some people suggest filling a new master cylinder with brake fluid before fitting it to the car, as an extra precaution against air being present. I am hopeful you will have this all solved very soon! As for the rears, the bias valve needs to be in the open position to let fluid passed, although I expect you are aware of this. Richard

Richard - thanks for that.  I was aware of the rear brake bias issue, but thanks for the tip about fitting the master cylinder "wet".

I have always used a vacuum device to bleed my Fulvia but I suspect positive pressure from above might do as well.   Perhaps the piston in the master cylinder is so far forward fluid cannot get in?  (hence, fill the cylinder first)   Positive pressure from the caliper upwards, such as I use on a motorcycle would get round that one - reverse bleeding.    Just a thought, have not had this particular problem myself.

I have always fitted S1 & S2 Fulvia brake master cylinders 'primed' and then I have always used the 'positive pressure' method using either a Gunson kit or (now) a home made method of clamping a lightly pressurised fluid reservoir to the Lancia fluid reservoir.
Always worked for me apart from one occasion when I didnt realise there was a 'rolling ball' rear brake bias cylinder with a bleed nipple on my GTE which was hidden between the rear of the gearbox and the rear of the subframe.
Chris

Some master cylinders do not have a front fluid feed hole from the reservoir to the front circuit but rely on the one way valve between the pistons to fill the front. These may be gummed up. Additionally I have found if there is a feed hole at the front it is small and sometimes aligned behind the piston. One one master cylinder I opened up the hole 1mm and this cured the feed problem.

Obviously is makes sense Norman to remove the master cylinder and give it a service anyway.

There is, incidentally, a diagram of the master cylinder in the technical information thread.

Thank you David, Chris and Tim for your input.  I've now removed the front calipers and they are with Classicar Automotive for refurbishment.  I've started the process of removing the master cylinder and will attempt to refurbish that myself with a repair kit.  It will be interesting to see what condition the cylinder bore is in.

The cross section digram of the master cylinder in the Technical Section will come in very handy.

It's interesting how you go down some blind alleys when working on a car.  The brake circuit diagram in the S2 owner's manual incorrectly shows the large front brake pistons at the bottom of the calipers, whereas the TAV and physical inspection confirm that they are in fact at the top of the calipers! 

I’ve now refurbished the master cylinder.  The objective was to see if it was a master cylinder problem that was causing me to get no fluid pressure at the front top caliper pistons.   Getting the front 32mm nut undone was the first challenge.  I tried with it still in the car, using a two foot breaker bar on the 32mm socket.  Wouldn’t budge.  Removed the master cylinder assembly from the car and held it in a vice.  Still no joy with the breaker bar.  A friend recommended trying an impact wrench - so I tried, somewhat sceptically, with my relatively low powered impact screwdriver and the shock waves did the job.

Note that the spring behind the nut is quite strong, and will likely shoot out.  It’s a good idea to label the spring, and to keep all components in order and with the correct orientation as they are removed, to assist in reassembly.  And note that the first spring that comes out is shorter than the second one.

I removed the front plunger, by first removing the limiter screw in the bottom of the front fluid chamber, and then pulling  the plunger out using a pair of long-nose pliers.  I removed the small circlip and pulled the various components off the plunger .  The two portions of the plunger can be separated by clamping one end in a soft-grip vice and levering the other portion off gently with a pair of screwdrivers.  

Then I removed the larger second plunger, by unscrewing the limiter screw from the bottom of the rear fluid chamber.  The plunger assembly was then withdrawn through the front, the same way as the first plunger had been removed.   It needed a gentle push from the rear with a wooden dowel, being careful not to scratch the bore.

I cleaned everything and inspected and cleared the holes that fluid passes through.  The component parts are shown in the breakdown picture below, with TAV reference numbers against each part.  I inspected the cylinder bore by sight and touch.  Mine was in exceptionally good condition, with no marks or corrosion detected.  Note that there is  a small o-ring just inside the rear of the cylinder body that should be removed/replaced and the groove that it sits in should be cleaned.  I cleaned the outside of the body with a small brass wire brush on my Dremel.

I had bought a repair kit, so next step was to identify where the seals and o-rings in the repair kit should be positioned.  Most were obvious, but I ended up with one seal left over. It was a seal identical to the one fitted to the rear plunger at TAV item 11.  Scratched my head for a while, and only when seeing a photograph of a front plunger for another Series 2 did I understand. Apparently, there are two designs of front plunger, and they are interchangeable.  They are shown side by side in one of the pictures below. The one in my car has a narrow groove that takes an o-ring at TAV item 38.  The flanges either side of the groove are of equal thickness.   The right hand picture shows the other design, with a wider groove that takes the same seal as used in the rear plunger.  The flanges in this version are of unequal width.  ***Beware** because the right hand design picture (which somebody sent me) shows the seal facing the wrong direction.

The repair kits from at least three suppliers contain both the o-ring and the seal, so anybody with a plunger like mine will end up with a spare seal left over.  Anybody with the other version will end up with an o-ring left over!  Of course there’s nothing with the kit to tell you this, and I’ve not seen it referenced in any of the manuals or forum threads on this subject!  

The TAV diagram seems to show my plunger design.  The TAV illustration is somewhat misleading as It does not show clearly that items 38 and 11 fit over the plungers, (rather than being positioned behind them), and somewhat confusingly labels item 38  as “connector”.

Fortunately the repair kit included a reservoir cap - useful as mine had become brittle and was dropping bits of rubber into the reservoir mesh filter.

On reassembly it is important to point the lips on the seals in the right direction, as I have illustrated in the disassembly picture.  I fitted new circlips to each of the plunger assemblies.  The assemblies are fed back in the same way they came out, using some brake fluid as a lubricant.  After each plunger is installed its limiter screw should be refitted in the base of the fluid bowl.  It’s worth holding the plunger alongside the cylinder body before fitting in order to see where the recess should be approximately positioned before the limiter screw is fitted.

I bench-tested the assembly by filling it with brake fluid and pressing the plunger repeatedly to check that fluid was being expelled through both front and rear brake line openings.  All seemed to be working correctly.

I have fitted the overhauled master cylinder (m/c) to the car, first checking that the nut on the front of the spindle projecting through the servo was flush with the front surface of the servo.  I replaced the large o-ring around the rear projection on the m/c body, that came with the m/c repair kit.

The front calipers came back shining brightly from Classicar Automotive.  Their charges were not that much more than an overhaul kit would have cost me, and the quality of their work seems to be excellent.  It seems like caliper refurbishment is popular at the moment judging by the boxes and boxes of calipers in Classicar’s small reception area, with yet more boxes arriving by courier as I waited to collect mine.  They quoted me two weeks to do mine but took four, and are now quoting six to eight weeks.

I fitted the calipers, using new split pins, anti-squeal shims (were missing) and new flexible brake pipes.  The brackets that hold the flexible pipes at their lower end are marked “A” and “M”, the A standing for Anteriore (front) circuit for the large top pistons in the front calipers,  and the M for Mixed circuit which controls the rear pistons and front lower pistons.    I then reconnected all five brake lines to the master cylinder, and tracked the two “A” front ones to make sure I had them connected to the correct (top) pistons on the front calipers.  Note that the Owner’s Handbook for the S2  incorrectly shows the large pistons at the bottom of the front calipers rather than at the top!  The three brake lines from the rear port on the master cylinder feed the Mixed circuit (rear and front lower).

I then bled the system, using the old fashioned gravity method with my wife pressing the brake pedal as I shouted “press” and then “release”.  I used a rubber tube into an overflow bottle - keeping the top of the tube above the level of the nipple.   I bled the left rear and then the right rear, then the left front lower and right front lower.  That took care of the Mixed circuit serving all 8 small caliper pistons.  I then bled the “A” circuit - front left upper followed by the front right upper.  As the system had been pretty much emptied of fluid before I started  I then repeated the entire bleeding process starting again at the rear to make sure all air was out of the system.   I probably used twice as much brake fluid as I needed to but wanted to be sure I’d thoroughly flushed out the old fluid as well as the air!

When the rears were being bled I had the car jacked up using the central axle jacking point to ensure that the balance limiter valve did not restrict fluid flow to the rear calipers.

I’m pleased to say that the problem I encountered a few weeks back - no fluid pressure at the front top pistons - did not repeat itself.  So the master cylinder overhaul seems to have cured the problem.  Although I found nothing untoward while overhauling, I suspect that condition of one or more of the old seals or o-rings may have been the cause of the problem.

A very useful posting.  Thank you very much for this.

I wanted to thank the OP for starting this thread, both informative and timely! I have engaged in the same process with my 71 Fulvia and while I am getting to the end of the process, I have to say that Norman's 'all I had to do was bleed it twice' would have been a most welcome episode in my garage. I rebuilt the master cylinder, installed braided lines and all new hard pipes front and rear, and had the excellent service at Bigg Red rebuild all four calipers. This all went back on the car like a piece of cake. And then the horror started.

I began with the pressurised method for the bleed and got a bit of traction. Then I went to a sucking system with a pump on the bleed nipple at each caliper. This got flow going to all pipes, Then I went with the traditional wife on the pedal method, and got a wee bit of pedal feel, but then perhaps let the MC level get too low and pumped air back INTO the system, so started from scratch with the Gunson. This morning I could get pedal feel after a few pumps and then went back to the Gunson which seems to finally be doing the trick. I don't know how many times I've walked around the car from caliper to caliper, but it seems to be paying off.
 
I also have to admire Norman's use of only twice as much brake fluid as required. I'm sure I've spilled the overflow jar enough to fill and bleed two or three Fulvias at this point!