Hello all -

I need to replace the four short rubber hose sections on the master-cylinder reservoir and then I'm sure bleeding to get out air; car is a 1978 US Left-Hand Drive.
To clarify; intent is to just change out the four short 2-1/2" sections of braided rubber hose on the reservoir / master cylinder - If I can safely get by without having to crack the caliber bleeders at least at this stage all the better.
1. Any overall tips?
2. Doable to safely change out the four rubber hoses for the reservoir / m-cylinder without full bleed via the caliber bleeders given these hoses are at a higher point in the system?

Best, Steve

 

You can if you are careful. But remember that you have to use special 7mm brake hose that will stand up to brake fluid. Most VW places that work on air-cooled Bugs will have it, or get it off eBay. Normal fuel hose won't work.

 

Thanks @jal1234 - I had read about sourcing hose from a VW shop during a search and should have mentioned intent to source as such; thanks for the FYI.

Any tips regarding care to take to avoid need to crack the bleeders on the calibers and thus a full brake bleed?
Best to suction out as much fluid from the reservoir?
Jack rear-end up to elevate rear some?

Note: Primary reason in trying to avoid cracking the bleeders is fear of the old bleeders being stuck. I am planning on changing out all the calibers but not in this immediate time-frame.

 

You'll want to suck out as much fluid as you can. Remember that brake fluid is a great paint remover. Just don't touch the brake pedal while the reservoir is disconnected.

 

If you mean the supply hose from the reservoir to the master cylinder, and if these are like the HE, yes you can. You need an assistant. The hard part is removing the hoses from the master cylinder plastic 90 degree spigots on the top of the master cylinder, if the hose is still tight there. A very sharp blade may help, used along the hose exterior to weaken its grip on the spigot; but do NOT go right through the hose or you will nick the plastic spigot. jacking up the opposite side of the car helps keep the fluid in the spigot too.
Remove the feed tubes from the reservoir and immediately get your helper to hold them up vertical to keep the fluid in them.
Carefully remove the metal joining tubes and hold up the tube that is fitted to the M/C.
You unbolt the reservoir, empty and clean it and fit the new exit tubes and the metal joiners to it.
Remove one of the tubes from the M/C and replace it with the new one, holding the new one upright too. The idea is that fluid stays in the round part of the spigot
Same with the second tube to spigot.
if you want to be 100% careful, using a syringe fill the spigot-tubes with fluid.
Now you join the clean reservoir, exit tubes and metal parts to the spigot-attached tubes, all the while keeping the spigot tubes well above the horizontal. The put enough fluid in the still-unattached reservoir to fill the pipes and reattach the reservoir. Top up reservoir.

 

I recently had to replace the master cylinder on my 1966 S Type and I simply couldn't get it to bleed. With the position of the ports I couldn't bench bleed it before installing either. I tried pressure bleeding and couldn't get the all the air out either.

Then I remembered touring the Jaguar factory and they certainly don't have guys at the wheels trying to bleed the air out. What they do is put the whole brake system under vacuum and then inject the brake fluid into a vacuum. I ended up using 5 hoses and 6 different fittings, but I was able to connect my vacuum pump from AC work to the brake reservoir. The fluid started boiling violently when I turned the vacuum pump on from all the air coming out of the system and I very quickly had a nice solid pedal.

However, you might want to actually bleed the system conventionally in order to get fresh fluid all through the system and ensure that any old fluid is flushed out. Brake fluid absorbs water from the atmosphere and should be changed every 2 years regardless of mileage.

 

If going that far and dumping the fluid which the op indicated a preference not to do don't go with the old DOT4 - put DOT5.1 in there - it doesn't harm paint and doesn't absorb water, it also works perfectly fine - ALL of my classics without exception are on DOT 5.1 synthetic fluid and it doesn't need changing every two years, because is doesn't absorb moisture it won't cause corrosion in cylinders and is far better for cars that see infrequent use.

To slacken a bleed screw give it a gentle tap square on the end, soak it for a couple of days with a mix of acetone and auto trans fluid (better than any commercial release agent), then make sure to use an appropriate spanner - do NOT use a 12 point or open ended, use either a flare nut spanner or preferably a 6 point socket, you need to shock it loose but not go all gorilla, just tap the end of whatever you are using gently until the screw turns. I've not broken off or rounded a bleed screw in decades.

I may try that vacuum idea myself !!

 

Thanks for all the input.
All done w/ new/correct hoses and clean - good firm pedal.