Brake pedal mushy after replacing everything

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88 Yugo GV

Replaced entire braking system besides the drums and one hardline. New master cylinder, wheel cylinders, calipers, pads, rotors, shoes, hoses and hardware. It appears well bled, I have bled the brakes multiple times and get nothing but fluid. However, the pedal doesn't do much till its halfway to the floor. If you stand on it, the brakes will lock up no problem, but its really mushy up to that point. I did not bench bleed the master cylinder, as I didn't have any spare flare nuts to make lines for bench bleeding(70s-80s FIAT/Yugo uses a M10x1.25, very rare). However I figured bench bleeding to be unecessary, as all the ports on the MC point straight up.

Air in the MC yes? How to get it out?

 

[jsnyder49090]

a 88 yugo well thats your first mistake lol maybe gravity bleed it

 

[KB2008X]

You have to bleed the master cylinder before you even attempt to bleed the wheel cylinders or calipers. No exceptions.

Keith

 

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With all the ports being on top of the cylinder, I would think, air being lighter than brake fluid, that it would float up and escape through the lines during normal bleeding.

 

[ag_ghost]

Google "how to bleed a master cylinder".

 

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I know how to bleed a master cylinder, and make the brake lines up to do so, however the M10x1.25 flare nuts needed are straight unobtanium, it would cost me in excess of $20 for three little nuts.

Is there another way than the bench bleed, line feeding back into the reservoir method?

 

[jjcom]

By the sounds of it, you should have managed to get all of the air out of the master cylinder. And the brakes will lock up, so I doubt there's air in the system. I would wonder if the rear shoes are adjusted all the way up. Might check that before trying to chase down any more air bubbles.

 

[KB2008X]

I don't mean to be rude, but you need to stop trying to figure out ways to avoid doing what is needed and spend that time on learning how to do it correctly.

Keith

 

[KB2008X]

After a quick 2 minute search online I found several sources for the supposedly, unobtanium M10x1.25 brake lines from which you can make bleeders.

Try this: http://xwebforums.org/showthread.php?t=16264

You know what you need to do. Just do it.

Keith

 

[CourierDriver]

Originally Posted By: KB2008X
I don't mean to be rude, but you need to stop trying to figure out ways to avoid doing what is needed and spend that time on learning how to do it correctly.

Keith
Best advice for all of us. When in doubt, take your ride to a specialist on the brakes. How much is your life worth? Notice I said when in doubt if you are not a brake fixer person..............

 

[mechtech2]

It is not always necessary to bench bleed a MC.
For now, tap on it with a screwdriver handle as the brake pedal is moved up and down.
Then rebleed the system.

 

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I don't mean to be rude, but I guess reading comprehension isn't a strength with all the armchair engineers out here. I KNOW THE "RIGHT" WAY OF DOING IT. If you don't have anything to add but that, then don't.

Originally Posted By: mechtech2
It is not always necessary to bench bleed a MC.
For now, tap on it with a screwdriver handle as the brake pedal is moved up and down.
Then rebleed the system.


Thanks will try this.

 

[KrisZ]

Originally Posted By: mechtech2
It is not always necessary to bench bleed a MC.
For now, tap on it with a screwdriver handle as the brake pedal is moved up and down.
Then rebleed the system.


Also, I would try the 2X4 trick. Basically wedge a piece of 2X4 between the seat and the brake pedal, making sure it is pressed down as hard as possible and leave it like that over night. The pressure should force all stubborn air pocket out.

Also, you can try bleeding the brakes with the car on, so that the brake assist provides more pressure.

Also, like someone already mentioned, unadjusted rear brake drums can cause late brake pedal engagement.

 

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The parking brake cable has been adjusted twice. They have a very slight drag dialed in. This car is fully self adjusting anyways(friction adjusters, not ratcheting screws).

Also, my Fiat 128 Haynes manual(same brakes) seems to indicate you do all the bleeding on this car at the wheels with conventional methods(hose in jar or open/close bleeder in synch with pedal pumping). No mention of bench bleeding

 

[yonyon]

Disclaimer: I don't know from Yugos so take my words with a tablespoon of salt.

Offhand I can't think of any car on which it is normal to adjust the parking brake to achieve a drag. I've come across a few (Ford, Mazda, Honda, and Kia) vehicles that suffered from low or soft pedal feel due to parking brake adjustment set too tight.

 

[cutter]

Perhaps the brakes don't work well because it's a Yugo.

 

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Originally Posted By: yonyon
Disclaimer: I don't know from Yugos so take my words with a tablespoon of salt.

Offhand I can't think of any car on which it is normal to adjust the parking brake to achieve a drag. I've come across a few (Ford, Mazda, Honda, and Kia) vehicles that suffered from low or soft pedal feel due to parking brake adjustment set too tight.


Adjusting the cable had very little effect, positive effect if anything. It was loose for a while as I had initially dialed it in with freshly painted drums that had some paint on the contact surface.