36 replies to this topic

[cal844]

The test on the MC tells me that there was air in the system.

Clamp a flex line then pump the pedal, if the pedal stays firm on the first pressyou have found the air.

If after the above test there's still air,
I give the pedal a few pumps and hold it pressed for an hour... To try and get the air to move to the end of the lines.

Keep the pressure on and make sure you have a section of tube over the bleed nipple (as it will spray fluid everywhere if the nipple isn't tubed)

Do this for each corner.


Then once you're happy give it one final bleed in the correct sequence.

Just my findings of bleeding a Black Tag MC and PDWA (FAM7821 original valve).

Cal

Edited by cal844, 23 June 2021 - 05:40 PM.

[Spider]

That's some good news on the Master Cylinder - process of elimination.

 

Next episode involves eliminating the infamous, much hated, PWDA Lannister and see where I end up.

 

The particular one you have is not the awful one that is often mentioned. They are usually reliable, however, keeping an open mind about it, yes, put your bleed nipples on the outputs of this and see how you go.

 

The reason I suspected your Master Cylinder earlier is if the pedal ends up on the floor as yours has been, either (i) there's an external leak in the system and that would be fairly obvious or (ii) there's an internal leak somewhere. The only place in the system I can think of where that can occur is in the Master, but you've ticked that one off.

 

Keep working through the system as you have been, the item to check after the PWDA would be the Inertia Valve, though, again, these are usually very reliable, but, keep an open mind !

 

 

Clamp a flex line then pump the pedal,
 

 

Sadly here Cal, barlar has Stainless Steel Flex Lines fitted, which you can't clamp off without damage. That was my first thought back on the last page, but on checking this is his opening post, it was a no-go.

[cal844]

That's some good news on the Master Cylinder - process of elimination.

Next episode involves eliminating the infamous, much hated, PWDA Lannister and see where I end up.

The particular one you have is not the awful one that is often mentioned. They are usually reliable, however, keeping an open mind about it, yes, put your bleed nipples on the outputs of this and see how you go.

The reason I suspected your Master Cylinder earlier is if the pedal ends up on the floor as yours has been, either (i) there's an external leak in the system and that would be fairly obvious or (ii) there's an internal leak somewhere. The only place in the system I can think of where that can occur is in the Master, but you've ticked that one off.

Keep working through the system as you have been, the item to check after the PWDA would be the Inertia Valve, though, again, these are usually very reliable, but, keep an open mind !

Clamp a flex line then pump the pedal,

Sadly here Cal, barlar has Stainless Steel Flex Lines fitted, which you can't clamp off without damage. That was my first thought back on the last page, but on checking this is his opening post, it was a no-go.

Ah yes I see, clamping stainless lines won't have a good outcome, my apologies for my poor memory!

I have to agree with using the bleed nipples on the Bulkhead mounted and inertia valve, a great work around!

Regards

Cal

[barlar]

Last night I made all new brake lines for the entire front system, thus eliminating the PWDA. I had to order a couple of female 3/8" (Sweden is a mm country and some imperial parts are still hard to get off the shelf) pipe connections, but they should arrive today and as soon as they do I'm anxious to continuing and see how it goes this time.

 

Again, I'm being very humble about it all. My brother swung by and helped me bleed the brakes last time, since it's obiously a 2 man job. I had for days tried it myself with gravity bleeding and other equipment, but what I couldn't do myself for several days took 20 min as soon as I had another pair of hands. Beleive it or not both me and my brother have been working and modifying other cars for the past 20 years, and we've never experienced the symptoms we had on this brake pedal. That's why I still can HOPE that it's not the master but indeed something else. Now the only old components in the entire system is the master (which is tested and seem OK) and the inertia valve. Fingers crossed!

[no66]

You can find inch unions at Biltema by the way  

Still think the master is giving you problems, but can  take the inertia valve off and tilt it back and forth, should hear the ball moving. 

[barlar]

Yep, believe me, Biltema (budget store) could be an official sponsor for this. Sadly they don't carry UNF female - female joint unions (only M10). All other unions are from Biltema.

 

You might be right in that it is the master, but I sincerely still hope not! Soon I'll know more since I'm picking up my joint unions this afternoon.

Edited by barlar, 24 June 2021 - 12:45 PM.

[InnoCooperExport]

I've not seen this mentioned so I thought I would just add this, if you do decide to change to the Yellow Band MC you will have to make new lines as they are Metric rather than UNF. 

 

The GMC159/160 is a strange-ish beast with two pistons connected by a piece of wire, if you decide to rebuild it at some point be aware that you must NEVER twist the cylinders inside to get them to release from the bore. If the secondary piston is stuck somehow you will destroy the MC and you will not be able to purchase replacement inners without finding another complete unite to break for parts. 

Edited by InnoCooperExport, 24 June 2021 - 08:19 PM.

[Ethel]

Little bit of an aside - The routing of the lines round the front subby will have been to allow the whole assembly to be built in the factory then fitted to the car with the fewest operations.

 

You could extend your "dead headed" test circuit to the outlets of the PDWA to make progress. Use steady pressure to avoid tripping the shuttle valve inside. The idea is if one circuit fails the pressure in the remaining one pushes the shuttle across to seal it off, tripping the switch on the way. There are seals inside so it should be dry behind the switch, it is possible for the seals to go so both circuits are effectively joined in to one.

[barlar]

And here the neverending story continues. We've celebrated midsummer in Sweden so sadly I had to socialize instead of being in the garage. After removing the PDWA it was dead easy bleeding the system. Could do it myself in 10 minutes. Sad part though, as many of you predicted, the master cylinder is toast as well. What I experienced previously was a combination of the two problems, but obviously both needs addressing. So I'm going to put in an order of a GMC227 from minispares, and while waiting for that I'm going to kill myself trying to get the rusted clevis and split pins out of the brake pedal 

[Ethel]

Just in case you weren't aware, the yellow band master has  funky pipe unions - M10x1 top, M12x1 bottom. The bottom is for the rear circuit.

[barlar]

Thanks for the info! Yes, I've seen this. I'm putting in an order to minispares as we speak, but I can't seem to find the M12 fitting. Do they carry that? Since it's metric, it wouldn't be a big hassle getting hold of it in Sweden though.

[Spider]

Thanks for the info! Yes, I've seen this. I'm putting in an order to minispares as we speak, but I can't seem to find the M12 fitting. Do they carry that? Since it's metric, it wouldn't be a big hassle getting hold of it in Sweden though.

 

I think Mini Spares have a fitting kit that included that fitting.

 

<Edit: Choices abound !

 

http://www.minispare...|Back to search

 

http://www.minispare...AU5654MS.aspx   >

 

Edited by Spider, 29 June 2021 - 09:16 AM.

[barlar]

Great, many thanks! 

[Ethel]

It is a bit of an oddity. The Minispares kit is to plumb one up to the FAM7821 valve used on 80's era cars. 

They can be found loose, but you may have to buy a handful. I made up a threaded insert to convert a Metro clutch master from 12 to 10, there are also adapters on Ebay - & banjo bolts, but it's harder to find a suitable banjo

[sonscar]

Hazy memory here but werent they sold as a conversion kit at one time?Steve..