Stumped Bleeding Brakes

Finally got around to installing my new brakes. New master cylinder, entirely new rear drums (Shoes, springs, retainers, wheel cylinders  and drums themselves.), new pads, rotors and hoses up front. Kept all the original hard lines as they were clear 1 month ago when I bled the system.

Now I'm stumped. Here's the situation:
LHD 1988 Cabriolet
9" Front Rotors
180mm Rear Drums
Car has proportioning valves(are they really needed?)
2 man method:
Front Right and Rear Left bleed properly
Front Left and Rear Right have nothing coming out.

if nothing coming out even from the front wheel then all it can be is be bad master cylinder or a blockage somewhere? could be a blocked bleed nipple, but to have both corners on the same circuit affected would take some bad luck. worth a look anyway

pop the reservoir off and look down the affected circuit hole make sure fluid can get inside from the reservoir, take the line off and blow down them too

Could never get a good pedal on the golfs until I bought one of those pressure jobbies. haven't used it in years but I think it takes pressure from an inflated tyre, probably various versions available.

aye the EZ bleed is the one I use, makes life easier

I thought bad master, but its brand new. Now I didn't bench bleed the master, because I learned of this after already installing it. It very well could be just a ton of air in the system still needing bled.

I'm going to stop by autozone to borrow a pressure bleeder to see if that helps. If not it's time to dig.

Maybe a reverse bleed or a vacuum bleed off the nipple  would help too.

Blade3562 said

Finally got around to installing my new brakes. New master cylinder, entirely new rear drums (Shoes, springs, retainers, wheel cylinders  and drums themselves.), new pads, rotors and hoses up front. Kept all the original hard lines as they were clear 1 month ago when I bled the system.

Now I'm stumped. Here's the situation:
LHD 1988 Cabriolet
9" Front Rotors
180mm Rear Drums
Car has proportioning valves(are they really needed?)
2 man method:
Front Right and Rear Left bleed properly
Front Left and Rear Right have nothing coming out.

Are Proportional Valves needed?  YES.  they prevent the rear brakes from locking up by reducing the pressure to the rears.  

At one time, VW on some Cabriolets and Golfs used a load sensing proportional valve located @ rear axle to increase or decrease the brakes on the rear.  Very pricy for repair of it.

As stated the Master is a cross diagonal unit, left front right rear and right front, and left rear.  So if you can bleed one side, then I would say that the master is wonky.  I have had new off the shelf units fail, and or reman units fail out of the box, bench bled and all.

You can make your own power bleeder for a few quid, there are plenty of how to's on the interweb.

I used the 2 people method for years, Trained the wife and kiddies on how to do it.

I have used a home made power bleeder for about 8 years know, and I won't go back, prior to that I used the speedy bleeder valves, which are spring loaded to stay closed.  You loosen them for about 1/2 turn, place hose over port, and press the pedal about 3 times, then close the port.. Worked really great.

I have also used a Mity-VAC tool, it has but one flaw, as I don't think it as a flaw but more as a OBTW…
It will pull air in from the threads of the bleeder port,  so you have to remove them and wrap the port in Teflon tape (yellow gas tape works best).  Be sure to poke a hole in the port after taping.  This is also a great tip to insure that your bleeder ports don't rust in the caliper or cylinders, and I have been doing that for years.

I also strongly state to create a bleeder catch jar out of an old Glass Pasta jar.  Drill two holes in the top.  Place about 3 foot of vinyl tune in one side about one inch from the bottom, and then a piece about one inch inside the top about 2 foot long.  Seal the vinyl hose with either RTV or JB-Weld (Epoxy).  You can bleed safely into the jar, or use it with your Mity-Vac to Pull new fluid through the entire system.

speedy bleeders:


Collection jar:
top


top and bottom:


Home Made Power Bleeder:

Totally stumped.  Tried bench bleeding (I think we did it properly). Looks like  I got a bad master cylinder. We tried reinstalling the old one and got the same exact results(It had a bad seal internally so I wasn't expecting much). I'm going to order a new reservoir as well.

We've invested probably 15 hours into this now and it's just so frustrating. Bleeding brakes should be so simple not this challenging lol.

I'll give it one last attempt tomorrow, but even a vacuum bleeder couldn't pull fluid through. What is The thread pitch on the brake fittings so I can buy proper plugs to try a better bench bleed on the master

Very frustrated at the moment. I'm not throwing in the towel just waving the white flag lol. Was hoping to make it to a show with it on Sunday but seems highly unlikely.

Ok bench bled the master (bought a kit) zero air bubbles in the master, got it bolted up and had to go to work. Just my luck.

Bench bleeding seems to have worked. We can constantly get the front right and rear left to bleed. But the front left and rear right will only bleed if one of the others that easily bleed has been bled first. So it was a back forth back forth night. Took it for a spin and the pedal travel seems great but it's unbelievably stiff. It must still need bled more but it was so excellent to drive it today! It will stop on a dime and lock up all 4 if you ask it to lol.

If the pedal is still stiff it may be the brake servo is not working ? Is it the same with either the engine on or off ?
If so, check the vacuum line into it.

make sure the check valve in the vac line is the right way round too. I've made that mistake before