Brake Master cylinder.

[Tajman]

Hello and seasons greetings and best wishes for the New Year to everybody.
About 3 weeks ago, I managed with the help of 3 mates ( socially distanced on each corner) to get the floor pan back onto the chassis after 15 months of strip down and rebuild. The floor pan had been extensively rebuild, so it was pleasing that it sat right on the chassis in position with a gentle nudge. Also to have it back in place was a major step forward.
Then it was all the fiddly stuff of connecting clutch cable, gear stick, choke, heater pipe,throttle, diff levers etc. Alot of which took more effort than I expected and some regrte that I should have done several jobs before placing the floor pan on the top of the chassis. Grovelling around under near trying to get split pins in clevis pins etc. After several motor bike accidents in a previous life, I have been left with an index finger replacing the thumb I lost.( Better than no thumb at all!) Two broken wrists that even though repaired, give me increasing discomfort as I get older. Upside down working against gravity, all amounts to that bit more hassle. Anyway if there's a will there's a way. I did eventually block up the whole vehicle to give me more working space.
All that seems to be on my list, before I put the front body work, screen etc. on, was the brakes, to connect up. I have replaced all the wheel cylinders, pipe work, low pressure and pressure side and a new master cylinder. My last project was the rebuild of a C202 Volvo Laplander that had a dual circuit brake system, 2 servos and a unique master cylinder, twin fluid resovoirs, complicated and gave me loads of grief. So thought Haflinger system? No problem! I bought some flexy stainless braided brake pipe with PTFE inner hose and end fittings from Car Builder Solutions. They have a great stock and very efficient service. This was for the join from solid on the chassis frame to the master cylinder, enabling me to lead it in a neat unobstructive way.
I screw the flared fitting into the master cylinder and proceeded to bleed brake and immediately it leaked there. It was then I realised that there was an intermeadiate fitting between the master cylinder and the pipe fitting. Luckily I had not thrown the old cylinder away so I took of the fitting , put on a new copper washer and refitted the hose.Good . At this point its worth mentioning that the master cylinder that Haflinger Technik supply, that I was using is different from the original. I believe it is same as used on VW.
I decide to bleed the system again using the Gunson Essi bleed 20 psi tyre pressure kit. I used the old grommet for the low pressure top up pipe pushed tightly in the top of the master cylinder with solid metal brake pipe flaired end into the grommet, as original.
After trying to bleed the back brakes for ages we tried the brake pedal and found that it would only depress an small amount. I then had to dismantle the master cylinder again to try and find out what the problem was. It turned out that if you push the grommit fully down in top of the cylinder , it actually blocks off the feed holes so hardly any fluid can pass through.The feed hole in the original cylinder is in the center. See pictures. As soon as it was introduced into the hole leaving it stick out a few mm, then the cylinder piston had full movement. So tomorrow is another day, and I might have some brakes working. Jeff

[heinkeljb]

hi Jeff,

Looks like you have found another one of the Haflinger's oddities of design. The rubber bung will leak if you don't get the pipe coming through it straight until after it leaves the bung. Now you have found that it doesn't let fluid into the cylinder if it is pushed in too far.

How about some more pictures of the build in progress?

John

[AustHaflinger]

Yes I have had issues with that stupid design - as John said the pipe needs to come out straight or otherwise the system leaks.

Garry

[Tajman]

Thanks John and Garry.
Another morning working with a mate, face mask on and trying to socially distance. Set it all up again. the stroke on the pedal /master cylinder was full but once again as we bleed the first rear wheel ( by hand , not with the gunson esii bleed kit) , the cylinder gradually locked up again with just about 10 mm movement on the piston. I removed it again, disconnected the pipes took out the grommit/bung, with cylinder on the bench, I pushed a tool into the rod end. Only 10 mm movement. I then pushed a tool carefully in the outlet end and the piston retracted and then I could operate it from the rod end normally, 30-40 mm movement. Something is going on in the cylinder. maybe a seal or air lock. I don't know. What I do know is these are after market products made cheaply, not branded. From what I see on the internet from VW parts suppliers, a branded master cylinder the same is £100 more. Anyway I am reluctant to take it apart as it may cancel the warranty. Haflinger Techink are closed till 6th Jan. Otherwise I am sure Dale or Ruth there would send a replacement. I have looked at the old rusty one that was in the vehicle, I know it had been standing for 15 years or more and the foot well must have got wet, judging by the rot. But when I operated it with some persuasion, it worked and clean brake fluid squirted out. I have it now in a container of WD 40/ diesel mix. I had a thought that I may strip it and see what the bores are like. Although I am reluctant to use it on the rebuild. I'll sleep on it and get on with something else for now. I have to finish fitting the hot air pipe underneath and on going task-- trace a couple of oil leaks.
Jeff.

[AustHaflinger]

Sorry Jeff your on your own on this one unless someone comes along who has a similar issue. I have had my master out but not had to dismantle it - as mentioned I just had the issue with a perished sealing bung and I got a new one from Haflinger Technik - it leaked until i worked out the metal pipe needed to go vertically in. Just a thought have you pushed the metal pipe in too far and this is catching the master cylinder?

Good luck with it.

Garry

[heinkeljb]

Hi Jeff,

From what you posted, it does sound like the piston is sticking in the bore. When you say you only get 10 mm of movement, is that at some point down the bore, at the top or at the bottom of the stroke?
The master cylinder is not that complicated, a piston with a couple of seals on it sliding up and down a bore. A spring to make the piston return to the end once it has been pushed down. Sounds like the spring is kinking and getting caught, possibly on the one of the fill holes if that has a burr on it.

I would take the master cylinder apart and see. If it is not something you can fix, then send it back with an explanation of the issue.

You could always take the old one apart and see if it is serviceable, all it needs is a clean smooth bore and seals which are not so hard that they don't provide a seal to the bore. You can always replace the cylinder when you get a replacement.

John

[Tajman]

Hi John,
I have taken the cylinder apart and found nothing untoward.See photo. Back together, I rigged it in the vice with outlet pipe into jam jar and Resovoir and fill pipe fitted, 4/5 pumps on the piston and it locked up only to allow the 10 mm movement again, same problem, took the fill pipe and rubber grommet out and no difference. I suspect the"Residual pressure check valve."-- The spring/seal thing in the bottom of the bore. I did also dismantle the old one and its not to bad, the seals are suspect. the quality is better. The after market new one I have does not look that brilliant in the way it has been machined. I see from research that there is the branded ATE master cylinder at a lot more money, but may be worth going for . COOL AIR VW spares suppliers list it but not in stock at £140 +. It the same cylinder as used in Beetle 1956 on. etc. Autoquariat list it at 225 euro.
I wonder if Haflinger Technik stock the ATE. I think now I will wait and talk to Dale there when they open again Jan 6/7th. Any other clues?
I have managed to fit the 60mm heater pipe from heat exchangers through to front foot well. Getting a bit crowded under that deck now, all that stuff. gear rod ,diff rod, handbrake cables etc. At least it all clean and painted. Dale gave me a second hand pipe as the original was well rusted through and bent alot. I had loads of fun trying to work out how to fit it and then realised he had given me a long wheel base one. I had to cut and join in 2 places to make it fit! Hope I will have a little bit of comforting warmth in the foot well, The heat exchanges were quite good and only required a a bit of welding around the pipe work after shot blast. They are massively made inside with big cast ally fins. I am eager to fit the front body and windscreen and dash board, as that would be a big step forward but for now , working on the brake pedal area is easier without.
Oh well last post for this strange year. Best wishes to all. Jeff.

[heinkeljb]

Hi Jeff,

Did you try putting just the piston and the spring in? It might be that the bore isn't round but oval. From memory, there ate some holes drilled in the end of the piston. If so, then obviously make sure they are open.
Have you tried putting your new internals into the old cylinder - if the bore is still nice and clean?

I found this for you which might be of interest:- https://www.machine7.com/product.php?xP ... 9&xSec=719

John

[Tajman]

Hello,
Today I think I made some progress with the Master brake cylinder saga.
I did strip it down again on the bench and compared side by side the old and the new. - See photos, the old parts are on top. It was obvious then that the seal/spring cap on the residual pressure check valve, was different. The old one is slightly larger diameter and the cap has holes in it! I then fitted the old one in the new cylinder and tried it out and of course it worked without locking up. So I now have to decide which direction to go. I don't feel confident using the old seal/residual pressure check valve in the new cylinder. Maybe I should bite the bullet and get a proper ATE branded cylinder. My Volvo C202 Laplander twin circuit master cylinder was re built and rebored by Past Parts in Norfolk as replacement was not available. Any way I will talk to Dale at Haflinger Technik and see what we can resolve. He has always be helpful in the past.
Jeff

[heinkeljb]

Hi Jeff,
Have you tried looking for a seal kit for the master cylinder? The place that rebuilt your Laplander can probably find you a kit and that should then solve the problem.

Might be worth a phone call.

John

[Tajman]

Well, at last the brakes are working. Although I have not moved the vehicle out yet but after fitting a new ATE master cylinder, all was well with the bleeding operation, and the brake pedal operating as it should. Thank you John for the link. I have used Machine 7 before and can recommend them for VW parts. So with this success, having been held back for over 3 weeks, I felt confident to put the front body work and screen in place at last. It was all ready to bolt on and within minutes seemed like a big step forward. Now to the wiring and fuel lines. Some one conveniently cut most of the wires in the cab area, maybe with the intention of removing it in the distant past. I got a wiring diagram form a very helpful forum member, in English and with coloured wires, that seems to be similar to reality. The local printer received the PDF and printed it out in A3 and laminated it and the list for 5 quid. Excellent! So spirits are high even with Covid lockdown outside in the real world.
I have attached a photo, The number plate is borrowed from my Volvo Laplander. I have yet to register the Haflinger. Frustratingly, I believe it was registered before as it has the holes for a British plate in the front body work and in the rear engine door. I found a Registration number scratched in the ally of the instrument panel. I sent that off to DVLA and they did not recognise it. So for the second time , soon I will have to apply for a date related reg. number.
Been working in the car port with the temperatures just above freezing and my quilted overalls on, Bet its awfully hot down under.
Bye for now. Jeff

[heinkeljb]

Glad things are moving forward for you. Always nice when you can see some progress. I remember having the front drive hubs all in piece when it was snowing so couldn't use Lurch in the sort of conditions which would have required a four wheel drive vehicle!

John