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Tried a MityVac to vacuum bleed the brakes on my "78 but that didn't seem to work. I searched and found posts here about how the lip seals will suck in air during vacuum bleeding. I got the suggested Motive Power Bleeder 0105 Kit.
First trying the 10psi air leak test but it was clear that there was a leak. After bleeding the hose on my compressor, I ran the pressure up to 10psi using quick disconnect fittings on the pump tank, no leak. The adapter was leak at the booster end. The surface has been clean, filed, etc. and no amount of fiddling with the chain/J-hooks could stop the leak. Tightening the chain at that end first helps but doesn't stop the leak. I can press firming with my hand and stop the leak.
I have one(wish I had two) C-clamp that fits over the MC with a hefty flat steel bad seems to hold. Only dropped 1psi in five minutes unless I have a leak elsewhere. I'll move onto the next step now.
That chain setup puts an awkward uneven pressure on the adapter plate, I think! It seems to be as the C-clamp seals the leak.
Anyone else run into this or am I just unlucky, maybe brain dead too??
I use a single quik-grip clamp on the center of the lid without any other 2x4 or plates.
I did find that if you put too-much pressure it bends the ends and starts to leak.
I only run about 15 psi and don't put any fluid in the jug, only top up the master.
Mooser
I haven't looked at the manual to see if they mention any max pressure for power bleeding yet. The Motive states 20psi max but so far I've put 10psi from my compressor and the hand pump.
I use a single quik-grip clamp on the center of the lid without any other 2x4 or plates.
I did find that if you put too-much pressure it bends the ends and starts to leak.
I only run about 15 psi and don't put any fluid in the jug, only top up the master.
Mooser
It would be pretty hard to blend that plate. The rubber is very pliable and your probably flattening it right out to the point of leaking.
If one needs to fill empty lines or do a flush, I'd put fluid in the bottle unless you want unclamp to fill as needed.
If you don't put the fluid in jug using a compressor instead of the hand pump would easily overcome any "minor" leak from the adapter plate.
The Motive 105 kit I bought about a month ago from Summit came with a thick aluminum plate. It sealed great. I only had one clamp when I took the picture. The chain sealed OK, it's just a hassle to put on. I'm guessing they realized the plastic plate was prone to leaks and so upgraded that part.
I got mine from Summit also! They are one day UPS or overnight if they use FedEx from me.
Is that a sliding bar type clamp? I have two like that but they have a 12" deep reach and I doubt they'd even fit in there. They must weigh about 20 lbs each.
It would be pretty hard to blend that plate. The rubber is very pliable and your probably flattening it right out to the point of leaking.
Bend was the wrong word.
If you clamp it too tight, mine tends to "tip" as the rubber compresses on whatever side of the centerline the clamp is on and it will leak out near the opposite end.
I've found that by getting it more or less in the center and then just lightly clamping it, pressurize the bottle and then just go easy and tighten it up until it stops leaking seems to work best (for me)
I've also found that the quik-grip type pistol-one handed clamp with the thick rubber pad on the ends works a lot easier than c-clamps. Conforms to the bottom of the master and doesn't try to move around as much
Mooser
Bend was the wrong word.
If you clamp it too tight, mine tends to "tip" as the rubber compresses on whatever side of the centerline the clamp is on and it will leak out near the opposite end.
I've found that by getting it more or less in the center and then just lightly clamping it, pressurize the bottle and then just go easy and tighten it up until it stops leaking seems to work best (for me)
I've also found that the quik-grip type pistol-one handed clamp with the thick rubber pad on the ends works a lot easier than c-clamps. Conforms to the bottom of the master and doesn't try to move around as much
Mooser
Mooser
I have a few of those types of clamps but they might not have the depth/reach needed for the MC. Have to look into that.
OMG! I left the C-clamp on since Wednesday and started to continue today. The MC was empty since I removed the old fluid so I wanted to fill the MC first. Not only was it stuck, had use the pump pressure to loosen it a bit but there was a heavy indentation in the rubber. The rubber seal has shifted on the plate also probably due to the awkward pressure from the chain. Luckily it's not enough to block the holes in the plate.
I had to fiddle with it to get it stopped from leaky on the air test because of the indentation, I think.
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
I know we have been using this pressure bleeder to push fluid through the system and out the calipers. The Phoenix Injector pump pushes fluid through from the caliper side and out at the master. I think this could be used to do the same job. I haven't tried my homemade version to do this but have been thinking of it for a few weeks now. When I get around to it I will give it a shot and report back. Hopefully someone will beat me to it.
Phoenix Injector pump22175]I know we have been using this pressure bleeder to push fluid through the system and out the calipers. The Phoenix Injector pump pushes fluid through from the caliper side and out at the master. I think this could be used to do the same job. I haven't tried my homemade version to do this but have been thinking of it for a few weeks now. When I get around to it I will give it a shot and report back. Hopefully someone will beat me to it.[/QUOTE]
From the looks of it at their site that system can either pressure bleed from the MC or vacuum bleed from the caliper or at least that's what they show.
I used to just have one filler port, but I added the other vent path with an isolation valve. Yes, the plate is "notched" underneath to allow pressurization of both sides.
NOTE: The second port is not really needed--I now have it blocked.
Last edited by carriljc; Apr 11, 2020 at 05:42 PM.
Reason: added photo after lousy pb delinked all pics
I made a pressure bleeder out of a garden sprayer and I pump it up to ~20 psig and then do bleeding.....I just pump it up again when it gets down to 10 psig or so.
I used shop vac with short piece of garden hose tapped to vacuum hose, while son was filling MC I was holding the vacuum on brake line...had all of them bled and working perfect in 10 minutes.
I did not seal it to the brake line, I just put the hose over it and let it pull gently, then did the same thing over bleed screw on caliper.
Motive Power Bleeder 0105 Kit
