How to prime the clutch MC and Slave
10-04-04, 07:20 AM
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How to prime the clutch MC and Slave
OK, I got a new clutch master cylinder (MC) and slave. Had to order the flexible line, which should be in today. Figured it was enough work getting to the bolts on both the MC and slave, that I would do it right so I would not have to do it again, soon. I put the MC back on. Waiting on the slave until the hose gets here, today. Question I have is how to "prime" the components? Do you prime the MC and slave? What is the best way to get the fluid into the components, pour it into the hole where the the hydraulic line connects?
10-04-04, 07:38 AM
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I understand the bleeding, but I keep reading (in past posts) that you have to "prime" it before getting to that step? And the posts are not clear on whether you need to prime the MC and slave? Or suggestions for how to get the brake fluid into the MC and/or slave.
10-04-04, 07:54 AM
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So installing the master and slave dry, filling the reservoir on the master, then just pumping the clutch (slowly) and using the bleed valve on the slave will get all the air out without “priming” either the master or slave?
10-04-04, 08:53 AM
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ALWAYS prime! It don't matter how short the damn line prime it. Before install, pour a bit of fluid down the bottle on the master cylinder and work the cylinder with a screw driver. The purpose is to lub it a bit before install.
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10-04-04, 12:37 PM
#8
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Bleading the system is also a little different.
Open the bleader, press the clutch and while it is down close the bleader, when fluid squirts at you with no air, then it is finished.
Open the bleader, press the clutch and while it is down close the bleader, when fluid squirts at you with no air, then it is finished.
10-04-04, 12:56 PM
#9
I just rebuilt my Clutch Master the other night. When we reconnected the lines, the system would not build pressure, no matter how much we tried to bleed it.
We disconnected the main clutch line from the cylinder, and poured clutch fluid into the one way valve. We pumped the pedal a few times until the fluid got sucked in and pushed out. This primed the MC.
After re-attaching everything and a little bleeding, the clutch is as good as new.
We disconnected the main clutch line from the cylinder, and poured clutch fluid into the one way valve. We pumped the pedal a few times until the fluid got sucked in and pushed out. This primed the MC.
After re-attaching everything and a little bleeding, the clutch is as good as new.
priming the clutch master is not NECESSARY
10-04-04, 06:26 PM
#13
What's a prime? 
We certainly didn't prime the clutch master and slave my friend and I installed on his '81 the other day. We just swapped them in and poured some fluid into the master and started performing the procedure Hades12 mentioned. It worked perfectly.
We certainly didn't prime the clutch master and slave my friend and I installed on his '81 the other day. We just swapped them in and poured some fluid into the master and started performing the procedure Hades12 mentioned. It worked perfectly.
10-04-04, 06:45 PM
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Originally Posted by Brianhsval
ALWAYS prime! It don't matter how short the damn line prime it. Before install, pour a bit of fluid down the bottle on the master cylinder and work the cylinder with a screw driver. The purpose is to lub it a bit before install.
Hey man, just saying what's always worked for me......
10-04-04, 08:01 PM
#17
ok is just installing a new clutch slave with the old clutch master cylinder (because i think its just my slave is giving me trouble) a bad idea.....and how hard is the job to install them?
10-04-04, 08:04 PM
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It is hit or miss, the master cylinder has a one way check valve built into it that works better when wet (with brake fluid). If you do not prime the master cylinder(pour some fluid in during rebuild) or at least make sure that the parts are coated with fluid, you only move air around the master cylinder when pumping the pedal, when dry the check valve is not as effective but may work. Best bet is to wet the parts before you put it back together like the manual says to and be on the safe side.
Dennis
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10-05-04, 07:19 AM
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Well, I've installed both the MC and slave (both new) without putting any brake fluid in either - is there an easy way to "prime" the master without removing it again? - can you remove the "hard line" from the MC and pour some brake fluid in there - or is that the "one way valve" that was brought up? - otherwise how do you get brake fluid into a new MC without disassembling it?
Any advice on how to finish this job would be most welcome
Any advice on how to finish this job would be most welcome
10-05-04, 07:26 AM
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PS: FYI - nopi.com had the best prices, followed by Olympus Imported Parts (www.forparts.com)
10-05-04, 10:41 AM
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Hey Wackey! WTF do yo think the purpose of priming is?? It isn't just to get it bleed faster it is also to insure lubrication. All around good mechanic work habit. Do what you like man, and yes, it will bleed without priming, but that was not my point. Think before you start calling someone BS!
10-05-04, 10:52 AM
#22
I could understand priming the brake master cylinder but clutch master? Give me a break...its a waste of time. why make things difficult. dont scream..get that cap lock off
In addition, its true that priming is commonly used..but its mainly used on shops due to $$. The faster you finish, the more cars you can do. My personal cars, no short cuts as I prefer to have fresh brake fluids.
In addition, its true that priming is commonly used..but its mainly used on shops due to $$. The faster you finish, the more cars you can do. My personal cars, no short cuts as I prefer to have fresh brake fluids.
Last edited by Siraniko; 10-05-04 at 11:05 AM.
10-05-04, 10:58 AM
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If you have already installed everything, and can't get it to prime, hook a long, preferably new hose up to your slave cylinder bleed, crack it open and suck (hard) thru the hose while someone else pushed the pedal down. May take a while.
dennis
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10-06-04, 07:04 AM
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OK, its done – thanks to all who provided advice – in summary, it was not a problem to bleed the system without priming – though its probably better to “bench prime” prior to installing – but if you don’t want to risk spilling a full reservoir and damaging paint (either inside the engine bay or fenders), then installing dry and doing a normal bleed worked for me
10-06-04, 08:21 AM
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Originally Posted by MACH7
PS: FYI - nopi.com had the best prices, followed by Olympus Imported Parts (www.forparts.com)
You must be in the DC Metro area. I didn't think they did internet orders.
Anyhow, what's the purpose of bench priming any master cylinder? I've replaced both clutch masters and brake masters... Just bolt em in, fill em up and bleed the system like normal.
