19 replies to this topic

[gaspen]

Hello

 

I am repair an Authi Mini, I started with the brakes. The car has a diagonal split brake system, see the first drawing.

 

There is a GMC227 master brake cylinder in the engine bay which "belongs" to a front to rear type system if I am right.

 

I'd like to ask your advice if I could rebuild the brake for a front to rear system with a intertia valve at the rear wheels or not

 

Thank you

 

 

 

Attached Files

•  diagonal split.gif   38.58K   2 downloads
•  front rear.jpg   34K   1 downloads

[richmondclassicsnorthwales]

As long as your brakes work and stop you and it is legal, Yes, you can build your own brake kit for the car.

 

 

Mindaddig, amíg a fékjeid megállnak, és megállítod, és törvényes, igen, építheted a saját fékkészletét az autóhoz.

 

What I also mean is as long as the equipment fits, is suitable for the Mini, then there is a lot of different things to be used, fitted and working

 

 

Amit én is jelentek, mindaddig, amíg a berendezés illeszkedik, alkalmas a Mini-ra, akkor sok különböző dolog használható, felszerelve és működőképes

 

 

Üdvözlet Neil

Edited by richmondclassicsnorthwales, 19 November 2018 - 08:24 PM.

[Swift_General]

Anything's possible. But you would need to think carefully about the rear wheel cylinder size, particularly as the master cylinder is stepped so even without the inertia valve you are introducing a pressure differential between front and rear that wouldn't normally be there.

[Itsaminithing]

Bence -you can use the Minispares chart to work out which rear cylinders & regulator valve to use with whichever master cylinder you choose.

http://www.minispare...rt.aspx?1~9~105

[gaspen]

Thanks folks

 

There are .75" cylinders on the rear (TRW) and GWC126/7 on the front from Minispares. All of them are brand new because the old ones was rusted inside.

 

I also want to buy a new master cylinder because its condition also :-/

 

The ID chart on Minispares does not shows my configuration.  Now I have GMC227 MC and 13H5905 4-way switch.

 

As I understand GMC227 produce different pressure in the two circuits.

 

Won't the 4-way switch indicate a fault in this case ?

[Spider]

I'd suggest doing away with the PDWA Switch (the '4 way switch') and run the lines straight through.

 

The GMC227 has a Float Level Switch in it's Lid and this is what's used with that to give an indication of a Hydraulic Brake Fault.

[Itsaminithing]

As above -remove the 13H5905 (someone will want to buy it) & buy a new GMC227.

I would also fit a MS72 adjustable brake pressure valve to the rear brake pipe for fine tuning of the brake balance.... https://www.calverst...-brake-systems/

[Swift_General]

The ID chart on Minispares does not shows my configuration. Now I have GMC227 MC and 13H5905 4-way switch.

I may be wrong but I think the inertia valve was a 70s thing and fitted to some export models, with the stepped cylinder coming later, so probably never fitted together from the factory. Is there a particular reason you want the inertia valve as use of the minispares adjustable as above is a good shout.

[gaspen]

 

The ID chart on Minispares does not shows my configuration. Now I have GMC227 MC and 13H5905 4-way switch.
 

I may be wrong but I think the inertia valve was a 70s thing and fitted to some export models, with the stepped cylinder coming later, so probably never fitted together from the factory. Is there a particular reason you want the inertia valve as use of the minispares adjustable as above is a good shout.

 

 

This Mini was built by Authi in Pamplona, Spain in 1975 and exported to Swiss. That's all I am sure of

 

I don't know what was its original config because the Authi parts catalog shows the domestic cars only. Those cars were equipped with single circuit brakes mostly.

 

I read somewhere that the intertia valve is recommended but I wouldn't pay for it if the GMC227 is enough by itself.

[Spider]

I think there was a build that did use the Inertia Valve and the Stepped Bore Master, but in any case, there's no reason why they can't be used together.

 

I gotta say, I actually prefer the Inertia Valve.

[gaspen]

Is this the intertia valve you are talking about ?

 

 

Attached Files

•  IMG_20181216_170736.jpg   54.9K   0 downloads

[Spider]

Is this the intertia valve you are talking about ?

 

Yes, that's the one

[gaspen]

 

Is this the intertia valve you are talking about ?

 

Yes, that's the one

 

 

Good news, because that one is mine 

Edited by gaspen, 19 December 2018 - 06:45 PM.

[gaspen]

Hello again

 

I'm done with the brake system, but there is some problen on the front. The brake shoes touch the brake drums without pressing the pedal. It is quite difficult to remove the drums because of the friction with the shoes. The adjusters are fully back. It seems that there is som pressure in the front circuit.

 

Before I installed the master cylinder (GMC227) I bled it on the bench. Did I do it well or it isn't necessary ? Could this be the cause of the error?

 

Thanks

[Spider]

Bench Bleeding the Master Cylinder is fine and I can't see that being your issue.

 

Hopefully, I can describe this next bit without loosing you !

 

First, just crack open the bleed nipple on that Brake a small bit and see if any fluid spurts out (it will be brief), that will show if there's residual pressure in the system causing this. If so, then read on.

 

Have a look at the Brake Pedal itself, up under where it;s hard to see, the part that returns back and connects to the Master Cylinder. Be sure that part of the Brake Pedal isn't touching the body. Ideally, you want 1 - 2 mm clearance here as a minimum. If it is making contact, you need to make some shims to put under the Master Cylinder to raise it up until you get that clearance.

 

If there is no clearance here, the seals in the Master Cylinder cover over the ports that release the fluid back in to the Reservoir. Because of the shape of the seals, they will allow fluid to pass by them in one direction, but not the other, so as you drive, with normal road vibration, it brings the brakes on 'automatically' until they lock. Old and swollen seals in the Master can cause the same thing.