Lifelongtoy

I was having a problem with the pedal going to the floor. I replaced the master and the slave. It works now but it won't hold pressure, so I have to double and triple clutch every time. I bled the system pretty good. And I'm getting bubbles in the master reservoir after pumping for a while. Any thoughts would be great.

mr toytech

try bleeding it again. if that dont work you may have got a bad master cylinder.

drew303

Try refitting the line that connects to the master (that leads down to the slave).. could be allowing air in.

Otherwise a faulty master cylinder. I've had a brand new brake cylinder leak. New parts can be defective, especially when buying afermarket and not OEM

SwampThing

Yep, either there's still air in the lines, faulty connection, bad line/s, or bad new master...

Do the easiest thing first. Have someone pump it while you look and see if you can see any brake fluid seeping out on the ground anywhere. That'll indicate a faulty connection, or a bad line/s. If you don't see anything dripping, rebleed the system. If that doesn't work, clamp all your brake lines (lock pliers or c-clamps work fine), and pump the brake. If it gets rock hard after a few pumps and stays hard your master is fine. If not, you got a defective master.

Lifelongtoy

There's a chance I didn't bleed it well enough. I'll try again. I don't see any leaks anywhere.

rezrunner92

I would say start with the farthest away bleeder, the left rear wheel cylinder....

Just kidding, not kidding about this part though, sometimes clutches can be an absolute PITA to get bled out properly. Add to that you don't do it very often and then there is the question of the new parts possibly being defective.
If you are going to bleed it again follow this procedure.

Fill the reservoir and get someone to sit in the truck and slowly apply pressure to the clutch as you crack the fitting at the master cylinder. Don't let the person in the cab get to the bottom of the stroke before you re tighten the fitting. Do this a couple of times to make sure there is no air in the master cylinder. Take care not to run the reservoir dry and suck air or you get to start over.

Attach a clear piece of snug fitting hose over the bleeder on the slave cylinder. Run the other end back into the top of the master cylinder with the cap off.
Pump away for as long as necessary. It will take a long time before you get all the air out of the line and you will have to have someone watch the master cylinder reservoir to make sure you don't run it dry.

Once you have the line and reservoir full of fluid continue pumping away for as long as it takes for you to not see ANY air bubbles in the line. You can occasionally hold the end of the hose up in between pumps to help bigger bubbles find their way out faster.

After that, continue pumping away for another 50 or 100 pumps. The pedal will not have resistance you are just trying to completely remove air from the system. If you like you can dispose of the first couple of pints of fluid instead of putting it in the reservoir put it in a bottle. Just make sure the end of the hose is higher than the master cylinder at all times.
After you are satisfied that all the air is out of the system, tighten the bleeder at the bottom and top off reservoir then bleed and adjust as normal.
Good Luck.
Edited for spelling.

Lifelongtoy

First thing in the mourning, thanks bud.

surf4runner

i think it the highest to lowest, going diagonally...


i had a bad line once that took 2 MC and 2 slaves to find the problem. no fluid leaks, but would lose pressure after 5-6 uses

89-4Runner

most likely bad master cylinder. I recently had a similar problem but was fixed with a new MC. I also have bled 4 different hydraulic clutches using the gravity method and they all worked perfect first shot... no air left in system and nice firm pedal...

drew303

good advice having the hose above the MC... didnt think about that.