CK5
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Going after a brake leak, wish me luck!
- Thread starter shima
- Start date
rampage
3/4 ton status
Does no harm to check, but as long as you have new, clean fluid coming out without any air bubbles then it’s fine.
The good news is that I got the job finished up without too many hiccups. Getting the master cylinder cap on was a total PITA. I had to tap it with a hammer to get it on.
The bad news is that my pedal is really soft now. The truck stops, but the pedal is damn near at the floor... and that's at low speed! I must have air in the lines or something. Everything's a hassle...
The bad news is that my pedal is really soft now. The truck stops, but the pedal is damn near at the floor... and that's at low speed! I must have air in the lines or something. Everything's a hassle...
rampage
3/4 ton status
Best way to bleed is with a pressure bleeder. I made one out of a garden sprayer as suggested earlier. It’s a one man job and easily flushes the lines.
Kain
3/4 ton status
keep bleeding till you have good pedal
Couple of other things to try before you start bleeding again.
First, a low firm pedal, is usually rear drum brakes way out of adjustment. I would jack up the rear wheels and adjust the rear drums first. Next, turn the truck off, hit the brakes a few times to release all the boost vacuum. Then press the pedal down firmly until it stops, assuming it does not bottom out. Hold pressure on it and see if it creeps down.
It should be hard as a rock and not moving at all.
If it feels spongy, you have air. If its hard but slowly creeps down, you either have a leak or a bad master cylinder.
You already know what a leak looks like, so if it creeps, check for one.
If no leak, its the master cylinder.
Unfortunately that is common these days. I know why, but not why now. When I was growing up, I bled the brakes on my old Jeep, and friend's cars all the time. And I don't remember ever having to replace the master afterwards.
I think maybe in the old days we had to bleed brakes more often, plus since all the cars were all drum brakes, it was common for the pedal to get low between adjustments, so the whole bore was used.
Nowadays, with disk brakes and self adjusting drums that work, the master cylinder plunger does not change its travel much over a long period of time.
When you start bleeding, the plunger goes all the way down into a part of the cylinder that has not been used in years. Inside there is all kinds of crud and maybe rust. That stuff damages the seals on the plunger, and causes it to let the fluid leak by.
First, a low firm pedal, is usually rear drum brakes way out of adjustment. I would jack up the rear wheels and adjust the rear drums first. Next, turn the truck off, hit the brakes a few times to release all the boost vacuum. Then press the pedal down firmly until it stops, assuming it does not bottom out. Hold pressure on it and see if it creeps down.
It should be hard as a rock and not moving at all.
If it feels spongy, you have air. If its hard but slowly creeps down, you either have a leak or a bad master cylinder.
You already know what a leak looks like, so if it creeps, check for one.
If no leak, its the master cylinder.
Unfortunately that is common these days. I know why, but not why now. When I was growing up, I bled the brakes on my old Jeep, and friend's cars all the time. And I don't remember ever having to replace the master afterwards.
I think maybe in the old days we had to bleed brakes more often, plus since all the cars were all drum brakes, it was common for the pedal to get low between adjustments, so the whole bore was used.
Nowadays, with disk brakes and self adjusting drums that work, the master cylinder plunger does not change its travel much over a long period of time.
When you start bleeding, the plunger goes all the way down into a part of the cylinder that has not been used in years. Inside there is all kinds of crud and maybe rust. That stuff damages the seals on the plunger, and causes it to let the fluid leak by.
I think I still have a leak. When replacing the banjo and crush washers, I noticed that the loop on the end of the brake line (the part that the banjo bolt goes through) was pretty rusty. Could this be causing the leak? Should I file it smooth, so that the crush washers aren't sandwiching a rusty surface? Also, I read that the torque for banjos is 22 ft. lbs... is that right?
Thanks all. This has turned into a bit of a nightmare.
Thanks all. This has turned into a bit of a nightmare.
rampage
3/4 ton status
No don’t file it smooth, IIRC there are concentric rings on the surface that the bolt goes through that the crush washers deform against to create a tight seal. You could probably use a wire brush to clean it off but it’s probably a good idea to replace the rubber hoses since those are probably the originals.
Thanks, @rampage. I'm happy to report that I got my brake pedal firm, finally!
If I disconnect the line to try and wire brush the brake line loop, do I have to bleed all four brakes again?
rampage
3/4 ton status
Just that one should be fine.
In that pic of your banjo fitting it looked cocked almost... Like the Tang sticking off the side is hitting rust or something in the groove it sits in.
It may just be the pic playing tricks on me. But you may want to look there too
It may just be the pic playing tricks on me. But you may want to look there too
Kain
3/4 ton status
if take it lose you have to bleed it it lets air in the line
I'm happy to report that I think I got the leak fixed. Only time will tell for sure, I suppose.
I disconnected the line, wire-brushed the brake line loop, and reseated the banjo + crush wasthers. Then I bled that line, and then bled the other disc brake line up front for shits and giggles. My pedal feels really strong now. Crossing my fingers that the leak doesn't show its ugly head again.
Thanks to everyone who responded, you guys are awesome.
Drew
I disconnected the line, wire-brushed the brake line loop, and reseated the banjo + crush wasthers. Then I bled that line, and then bled the other disc brake line up front for shits and giggles. My pedal feels really strong now. Crossing my fingers that the leak doesn't show its ugly head again.
Thanks to everyone who responded, you guys are awesome.
Drew
rampage
3/4 ton status
Just an FYI: you can’t reuse crush washers - they’re one and done items. So if you reused the new one you had on there and it leaks again then you’ll know why.
hit or miss on this . . . seen and used them both ways over the years .
Yes, get one with a pressure release and make your adapters out of old m/c covers.
