72 replies to this topic

[Ethel]

That does look like a good job

 

A little tip for anyone doing the same: With the lever rates involved a few mm can make a lot of difference, so figure out a pattern, or jig to put the hole back as close to original before you weld it up.

 

You could even drill a couple of small holes in the pedal crank to pin a guide on. Drill it through the clevis hole, then drill the new hole through that.

[stuart bowes]

that's a good point, I measured off the other one and figured well if anything being slightly high is better than being slightly low and it ended up just slightly above centre 

[stuart bowes]

just realise you probably meant 'distance outwards from the pivot point'...

I guess the closer it is to the pivot, the more strength you apply to the brake (pedal effort is easier) but you have to push it slightly further

conversely the further from the pivot, input effort is slightly reduced (pedal effort is harder) but you don't have to push it quite as far.. have I got that the right way around ..

I can't see 2-3mm or so making a huge deal of difference really but the main thing I suppose is you hit full braking before you hit the bulkhead

I'm assuming that in normal conditions there's a good inch or so gap between pedal and bulkhead at full pressing.. ?

Edited by stuart bowes, 19 April 2024 - 06:43 PM.

[mbolt998]

 

These tools are also super handy when working on the Brakes for things like Cylinder replacement as you can lock off the hose and swap out cylinders without making a huge mess.

 

You've also mentioned the Master Cylinder and Regulator. These maybe the issue but that you say you can get a solid pedal and that they are not leaking tends to make me think they are OK - that's not a guarantee though !

 

 

OK another update to this. I bled the brakes again, using a bit more pressure on the EZ bleed (20psi) and they're much more solid. There must have been still a bit of air in there. I then tried overdoing the front adjusters (basically locking the brakes) and the pedal was very high and firm. So I'm convinced there are no issues. Backed them off to a normal adjustment and went for a drive. Everything working beautifully and can heel and toe like a boss.

[stuart bowes]

[Spider]

OK another update to this. I bled the brakes again, using a bit more pressure on the EZ bleed (20psi) and they're much more solid. There must have been still a bit of air in there. I then tried overdoing the front adjusters (basically locking the brakes) and the pedal was very high and firm. So I'm convinced there are no issues. Backed them off to a normal adjustment and went for a drive. Everything working beautifully and can heel and toe like a boss.

 

 

Good work

I actually find the Easy Bleed good for getting a dry system started in regards to bleeding, but to get all the air out not so good. I've found the old skool method of pumping the pedal with a hose and a jar on the other end a more reliable way of getting all the air out.

Pleased to hear you have a better result.
 

[mbolt998]

 

OK another update to this. I bled the brakes again, using a bit more pressure on the EZ bleed (20psi) and they're much more solid. There must have been still a bit of air in there. I then tried overdoing the front adjusters (basically locking the brakes) and the pedal was very high and firm. So I'm convinced there are no issues. Backed them off to a normal adjustment and went for a drive. Everything working beautifully and can heel and toe like a boss.

 

 

Good work

I actually find the Easy Bleed good for getting a dry system started in regards to bleeding, but to get all the air out not so good. I've found the old skool method of pumping the pedal with a hose and a jar on the other end a more reliable way of getting all the air out.

Pleased to hear you have a better result.
 

 

That's interesting about the old skool method. The way I have always found that the way that works the best is to build pressure, hold it, open the bleed screw, let the pedal drop to the floor and close it again. Repeat a few times. I think the higher pressure in the lines helps push the bubbles to the end. But on a completely dry system it's hard to get any pressure at all. I increased the pressure in the EZ a bit and also left it connected up while I looked for my spanners and bits of plastic tube so maybe that helped.

[Jimnz]

 

So, my question is, what system to reinstall?

 

I'd suggest your first port of call would be your local rules in NZ as to what the car should have been fitted with when new to comply and then check further to see what modifications you are allowed to do, to what level and if any engineering certification(s) might be needed.

 

 

Hi all, I have spoken to the Re certification people and as long as I am installing original designed parts, or upgrade designed parts for a mini, i.e. AP style calipers or minisport 4pot alloy calipers, I do not need any form of engineering certificate. Just proof that its mini specific parts, not some ad-hoc collection of bits. Which is doable, just harder and more hoops.

 

To save any heartache later I will go for the 4 pot minisport alloy calipers with solid disk now from the start of the process. Vanity reasons and they take photograph evidence of the modifications from original.

 

My first choice is to go with the diagonal split 1275GT system with the GMC167 MC and 1/2" rear cylinders and no rear valve. As I said before this is easier to copy the original lines from.

 

Second choice is the front to rear tandem, with the GMC227 MC, 3/4" rear cylinders and the PDWA FAM7821 valve, in line with what one version of the 1275GT had in 78.

 

Opinions, pointers on my choices before I buy?

 

cheers Jim.

[Spider]

Opinions, pointers on my choices before I buy?

 

 

Working with Factory Parts, I'd suggest a GMC227 Master Cylinder (since you'd like to run a tandem Master), a 13H7757 Valve for the rear brakes and 11/16" Wheel Cylinders in the Rears. The FAM7821 isn't a PDWA Valve but a pressure shut off valve. They would also have to be the worst valve they ever came out with.

For Calipers, the Metro 4 pots in the non-vented type are an easy choice in sticking with factory parts. In their vented versions, they were fitted to the ERA Turbo, though I can't see a vented disc is warranted on any Mini, they also add a lot of unsprung weight as well as increasing the scrub radius on the front wheels.


 

[alpder]

 

OK another update to this. I bled the brakes again, using a bit more pressure on the EZ bleed (20psi) and they're much more solid. There must have been still a bit of air in there. I then tried overdoing the front adjusters (basically locking the brakes) and the pedal was very high and firm. So I'm convinced there are no issues. Backed them off to a normal adjustment and went for a drive. Everything working beautifully and can heel and toe like a boss.

 

 

Good work

I actually find the Easy Bleed good for getting a dry system started in regards to bleeding, but to get all the air out not so good. I've found the old skool method of pumping the pedal with a hose and a jar on the other end a more reliable way of getting all the air out.

Pleased to hear you have a better result.
 

 

I'd strongly second this... a good bit of flow speed is needed to drag bubbles out from places like the drum slave cylinders and the rear brake limiter, because the outlets are not always at the highest points on those parts. I easi-bleed and then afterwards get someone to rapidly press the pedal with the easi-bleed still connected while I do the trad thing of open/close the nipple in sync - and always the pumping gets some more air out of the rears and firms up the pedal.

[miniGTS]

So after rebuilding my brake master and changing all brake lines to run a front/rear split system I was hopeful. No leaks on the new lines and flares all seem to seal well. Then I noticed a leak on the master cylinder where the plastic switch turns in. A leak there indicates something not right in the master cylinder chambers, correct? Because normally that leak would trigger the switch to light up.

So, I'm thinking maybe it's better to just get a new single line master. This would mean minor changes to the lines in front which is not a issue.

Am I correct that everything else will stay as it is except I will have a single line from master to a 3 way connection. From there one line to the front and one line to the rear.

On the rear I have a pressure regulating valve and 5/8 wheel cylinders.

Nothing else to change?

[Spider]

Yes, your Master Cylinder does have an issue and one that for the medium and longer term can be quite expensive to repair. I agree that replacing it would be the wisest path here.

 

In regards to going to a Single Circuit Master Cylinder, the only word of caution I'll raise here is beware you don't fall foul of your local laws. I'd suggest making some enquires here first.

If all that is OK, then I can't see any other issue here.

 

< Edit: Refer post #33 here  https://www.theminif...ow-tight/page-3 >

Edited by Spider, 23 June 2024 - 01:24 AM.

[miniGTS]

Thanks, it's not an issue with the local laws.

I'll first check the o rings as you suggested in your other reply. If it still leaks then I just get a new single line master. Then everything in the brake system will be new.