Manky's Pop.

[kapri]

Bleed the entire back brake system first ,starting at servo and then go to the back nipples themselves. Then bleed the front by the same method and then redo back to be sure. By manual bleeding the first chamber on the m/c is the rear set up and if that has air in it then it won't push the front chamber far enough;-)

There's actually a stop built in to the internal mechanism that locks against the front of the cylinder when front brakes fail so you need to have full volume / stroke in rear section to bleed front correctly.

[Manky Monkey]

No problem. Thanks for the info Kev.
Sorry Terry, I'll check with you first next time 

[lunatic]

There's just a little air in between the cylinder and the servo, that's it. No need for everyone to complicate it. A combination of manual bleeding and the vacuum bleeder will sort it. Why didn't we use a pressure one? Well, 3 weeks of messing about last time isn't what I'd call successful, thought this May be more effective. Long term I think it's move the servo time!

[Olds]

Has anyone tried driving it without a servo ?

[terry t]

There's just a little air in between the cylinder and the servo, that's it. No need for everyone to complicate it. A combination of manual bleeding and the vacuum bleeder will sort it. Why didn't we use a pressure one? Well, 3 weeks of messing about last time isn't what I'd call successful, thought this May be more effective. Long term I think it's move the servo time!

the 3 weeks was sorting the brakes out not just bleeding

[kapri]

Nah, was more like 3 months sorting the brakes out!

[Manky Monkey]

Yeah, the brakes were the major problem when we were struggling to get the truck through the SVA registration test, but thanks to the combined efforts of several superstars here, including Terry, they eventually passed with flying colours -the examiner used a pressure meter strapped to his foot to compare the pedal pressure with the braking efficiency at the wheels, so there was no way we could bodge it. When they're sorted, they're as good as any modern car, but bleeding them's always been a bugger.
We probably don't need a servo Dave, but at the time, we weren't sure. No idea what the pedal ratio etc's like, but I find it fun to drive, which is all that matters to me.
Kev, didn't the front brakes have to lock up before the rears for the test?  

[Manky Monkey]

Finally got the use of my laptop back, so I can post photos again. I've got a contract with 3, which covers my phone & broadband. Trouble is, when I've used up my broadband allowance for the month, there's no way of topping it up, although I can still access the 'net on my phone.
Anyway, not much to report, but here's a couple of fuzzy snaps.
Got to the workshop late today after a day of trudging the streets delivering the Mail in the rain. No Loony, so rather than tackle the brakes again, I spent a couple of hours painting the chassis & front suspension -I figured at least we can get the engine in then, even if the brakes still need work. As soon as the daylight started to fade though, it got very cold, very quickly. I ended up brush painting by torchlight. Looks good in the dark, but will probably look horrendous tomorrow. Just hoping the paint will actually dry now.
This was the brown etch primer.

[Manky Monkey]

And this is the black enamel chassis paint.

[Manky Monkey]

You can see the copper brake lines here, running from under the driver's floor, up the bulkhead & into the servo under the dash, then out again, through the bulkhead on the passenger side & down to the front & rear brakes.
I've replaced the 2 pipes on the driver's side after nicking one of them with the angle grinder while working on the bulkhead. All 4 brake connections have been apart over the Summer because I took the mudguard mounts off to powder coat them & the pipes pass through holes in the brackets. So the whole system needs properly bleeding.

[Manky Monkey]

The interior's looking a bit of a mess at the moment, with everything covered in filler dust from the roof & the dash stripped out -Mr Olds has wired in the new switches & added multi pin connectors to the dash loom to make future removal easier.
You can see the other end of the brake pipes I've replaced through the access panel in the floor. They connect to the master cylinder via a pair of residual valves, (the purple cylinders), which keep a small amount of pressure in the brake lines to stop the "drain back" of fluid we were getting, (if the truck was left overnight the pedal would need pumping up in the morning to work. The valves have fixed that).
The brake master cylinder & reservoir are under the driver's seat.

[kapri]

Yeah, the brakes were the major problem when we were struggling to get the truck through the SVA registration test, but thanks to the combined efforts of several superstars here, including Terry, they eventually passed with flying colours -the examiner used a pressure meter strapped to his foot to compare the pedal pressure with the braking efficiency at the wheels, so there was no way we could bodge it. When they're sorted, they're as good as any modern car, but bleeding them's always been a bugger.
We probably don't need a servo Dave, but at the time, we weren't sure. No idea what the pedal ratio etc's like, but I find it fun to drive, which is all that matters to me.
Kev, didn't the front brakes have to lock up before the rears for the test?  

Yup, front do have to lock before rears but that's to do with line pressures, grip area , tread width blah blah blah rather than m/c internals. MC bore is too big to run without servo as line pressure will be greatyl reduced as we already have a high pedal ratio.

Internally tandem mc  has methods of ensuring that whichever system fails the mechanical interlock will make sure that the other part works .Hence the front one has a stop that is miles' clear of the bottom of the m/c under normal bled function to ensure the rears still have something to push against. Easier to show than explain.

As Loony has already said they worked fine before , it's just remembering the knack of bleeding them.

[kapri]

You can see the copper brake lines here, running from under the driver's floor, up the bulkhead & into the servo under the dash, then out again, through the bulkhead on the passenger side & down to the front & rear brakes.
I've replaced the 2 pipes on the driver's side after nicking one of them with the angle grinder while working on the bulkhead. All 4 brake connections have been apart over the Summer because I took the mudguard mounts off to powder coat them & the pipes pass through holes in the brackets. So the whole system needs properly bleeding.

Must say those pipes do look cool;-)

[Manky Monkey]

Green & copper go together well don't they. 
We're due a drier day tomorrow, so hopefully we can get the damn brakes sorted & move on.
When I first arrived this afternoon I knocked down a couple of high spots in the roof & threw on the last of my fine grade filler. Obviously the roof's not a priority, but at least the filler's there, ready to be rubbed down if I get a chance. It looks thick, but it's only about 5mm at the deepest point. It's just spread over a wide area. It's still a little ripply in places, but considering we've made this from panels from 3 different manufacturers, from 3 different decades, it ain't too bad.

[Manky Monkey]

The Sealey vacuum brake bleeding thingy.