DOT4 to DOT 5 Silicon

[Lobo]

Nope, no servo assist, and yep, whilst I haven’t, I do reckon I could lock the front brakes with effort.
I too was coming to the conclusion that it isn’t worth it, purely on the safety concern of ‘the unknown’ … coupled to the fact that the stopping power is minimal at best - in modern traffic there’s little room for error. Given that realistically, there is indeed little on-going maintenance with DOT 4; I should perhaps stay here.

Trig, the car indeed is a Classic, but realistically a genuine work horse, and used daily. I’m not overly precious about her; more than once I’ve had to go into the books to check the allowable axle loads 😂.

[K2-K6]

Simon, is it a single bore mastercylinder pushing into whole system back and front too  ?

[Lobo]

Yep Nige, single bore / dual reservoirs isolating front & rear brakes.

[McCabe-Thiele (Ted)]

Dot 5.1 is a synthetic based fluid developed for ABS systems for the small price difference I've gone to 5.1 on both our cars the bikes 5.0.
A lot is down to personal choice a good branded Dot4 is probably better than a cheap 5.1.

[K2-K6]

I do think currently uninformed opinion demonising dot4 is giving a big skew to these things out on the great wide interweb.

All of them will work reliably and we sensible types on here can see the pros and cons of each in relatively serene surroundings   

They really are nuts about it in cycles, but they do use something that could be of interest Simon. The use of syringes to dispense fluid is routine.  That may offer you a very convenient access and fill option for your mastercylinder location as they are routinely using a pipe, sometimes with a little clamp to hold fluid while moving it about for convenient non drip use.
"Bleed kit" for Sram/Avid or Hope brakes which use Dot 4 / 5.1 fluids generally would have the appropriate seals for this application. they are not usually of any great cost.

Most of the others use mineral oil, a la Citröen system of old.

[Lobo]

Thanks to all who have contributed here; I do of course use the internet, but tbh place greater trust on the folk I know here as the knowledges and experiences will be genuine. I’ll be sticking with DOT 4 mainly due lack of current interest in spending more time on my back under the car (changing seals etc) - I’ve done enough for now! If next year I get the urge to change all the seals DOT 5 Silicon may yet happen.

I’ve a box of syringes Nige, and due the rear slave cylinders having the bleed nipples BELOW the brake pipes figured I’d give it a try to fill the lines ‘in reverse’, ie syringing in fluid from the slaves, and syringing the excess out from the master. It’s only me avail for this, so might work out easier. We’ll see… no biggy if proves unsuccessful.

[K2-K6]

You may have such a device already, I make a brake bleed pipe/valve as follows;- thick wall small rubber hose (motor factors supply) that fits tight onto bleed nipple, push a bolt tightly into opposite end to seal it, then put a slit in one wall about 20mm long and roughly the same distance from clearing bolt end.

This makes the cheapest, best sealing little one way valve I've used to bleed with. Just open nipple 1/4 turn with this already in place, then you can pump as many times as you want while watching the reservoir level to bleed any line through.  It's tradition that you may catch the outflow in a raspberry jam jar as part of this function  strawberry being far too posh 

Used on any numberr of complex brake systems, such as pumped six way anti lock type with various nooks and crannies.  Works very simply to never alow air to go backwards, so particularly efficient and quick to do on your own. You just don't need any assistance. That one way valve will let you walk round to the furthest point to lock it off as is doesn't need any monitoring.

It's so good, that should you need to replace fluid at any time, then if you can reach the bleed nipple without jacking, it will take about 5 mins a wheel.

[McCabe-Thiele (Ted)]

I’ve a box of syringes Nige, and due the rear slave cylinders having the bleed nipples BELOW the brake pipes figured I’d give it a try to fill the lines ‘in reverse’, ie syringing in fluid from the slaves, and syringing the excess out from the master. It’s only me avail for this, so might work out easier. We’ll see… no biggy if proves unsuccessful.

I think you will find the fluid friction makes it extremely difficult if not impossible to enable brake fluid to be pushed out of a syringe via a disc or wheel cylinder all the way via any three way connectors to the master cylinder on a car.
I've done it on my 400 (with 300 ml syringe) but that's just a relatively short set of pipework to the master cylinder.

What does work is if you use a large syringe (after initial first bleed using the brake pedal) to create a vacuum to pull out residual air bubbles. Using a syringe on an empty brake system has not worked for me as you can draw air in past healthy wheel cylinder seals. I've used an Easi-bleed kit to pump it down from the top if the master cylinder is  cap vented only.

The valved bleed hoses mentioned  above are pretty good you can buy them ready made - the hose lasts for over a decade.

.https://www.ebay.co.uk/itm/255004087399?epid=1130461392&hash=item3b5f6d9467:g:pNQAAOSws29bxgdw&amdata=enc%3AAQAHAAAAoD2Q6XcZob5YH4SOkrp7PuZUmC9MBofJv9KCOeKKUR1IW9V1BOzJqJ0NbflWhPZri%2BbP3E3Rn%2Bv6%2FtiN4nzkbAbuQzz%2FsxFq9kRlF0boDc4N5ANr8yZa3%2FWVyA61ZumqTUzI0vi3uYY5kRQUO94NJ56LKn09JBvmWncy72xtycDVrjJVgqqAkXAVp98x51zgcONk7oymr1BuBhZ2ewSwtrQ%3D%7Ctkp%3ABk9SR7CZoNC6YQ

 

[K2-K6]

I make them longer Ted so that you can have a standard issue jam jar standing on the floor rather than try to balance it on something 

[McCabe-Thiele (Ted)]

I make them longer Ted so that you can have a standard issue jam jar standing on the floor rather than try to balance it on something 

I bought two pipes cut off the end stop & slit - joined with some Kunifer copper slightly angled brake pipe  to get a similar outcome.

[Lobo]

Thanks for the tips Nige / Ted - the rubber fuel pipe with slit worked perfectly, and with a mod to your jam jar using a 2L plastic milk bottle with interference fit on the hose. It consequently sits happily anywhere and at any angle - I bled all 4 corners in about 30 mins via the conventional method.

The car all buttoned up until next time - rewiring he mid year + likely engine out / new gaskets as a bit too oily tbh.

[McCabe-Thiele (Ted)]

Good outcome - fwiw my jam jar has now been upgraded to a see through thick plastic bottle (ex-PLJ) I think it was.

You mention - a bit too oily - what type of crankcase breathing system does it have if any? 

When BL introduced the positive crank case breather system to the old A series engines it was a wonder cure - likewise on the old Opel 1900 cam in head engines.
Just  thought I would put it out there for consideration.

[K2-K6]

Good to get it all completed Simon. Those little tube make quite a difference in that it seals virtually perfectly and such a simple device too. They make even complex system very easy to bleed even new ABS etc.

Did you mean negative crankcase pressure Ted ? I thought they all pulled slight vacuum on the cases to avoid pressure trying to push oil out of any seals etc. It may have come from Buick V8 when they bought that as originally it was arranged this way, V8 being quite a windy arrangement in terms of case volumes vs piston volume and movement.  I've a injected one now that has dipstick sealed which if removed you can hear the idle air valve compensate for the increased flow pulled through the cases.
We test them with a rubber glove on the oil filler to see if it inflates or sucks in assessing if working correctly.  In bad cases the valley gasket is pushed upwards under the inlet manifold if they've not been looked after well, that because of pressure building up to much.

VW has many sealing faces with barrels, heads, pushrod tubes etc all individual components to seal too.

[Lobo]

Thanks Ted, a bit of lateral thinking that - never considered that.
Nige… somehow I’d have though exploding gases loaded up a crankcase pressure if anything vs dropping it below ambient - a bit confused here!

Ted - a breather next to the oil filler vents to the air filter, which is basically an oil bath used to trap particles. The upper 1/2 of the engine is ‘acceptably’ clean.
Below the air-flow baffling (ie ducted tin-ware over the cylinder heads) it’s a different matter - the lower engine is fairly damp with congealed oil. I’m guessing years of weeps as Nigel alludes to with chaotic air flow all making one horrible mess… (the lower engine is a bit wetter than the pic suggests)

[K2-K6]

Thanks Ted, a bit of lateral thinking that - never considered that.
Nige… somehow I’d have though exploding gases loaded up a crankcase pressure if anything vs dropping it below ambient - a bit confused here!

Yes, i wasn't clear there. The cases venting into inlet tract on engine side of throttle plate (carburettor or injection) pulls constant vacuum on crankcase void to keep it "empty" in effect. But as noted, if that supply is too great it or shifting, it can affect idle rpm hence the dipstick has a seal at the top to prevent it sucking in through there.
One of the checks is to pull the dipstick on this, revs should go up, then by pulled back down to target as ecu modulates the air bypass route to adjust.
It fails if pipes/flame traps etc are not maintained and flow impaired.