No brakes after blowing rear diff

[tellurunner]

So I was in Moab about a month ago and my truck suffered some major carnage. My rear diff blew up and soon after front cv went out. I replaced the front CV on the trail with my buddy's spare. Unforunately his CV had mangled threads and I couldn't get the axle nut all the way on tight. I limped off the trail but noticed decreased braking power and by the end had hardly any brakes at all.

Fast forward til today, I have replaced the rear diff, CV's, front bearings (because the one was shot due to axle nut not being tight) and I did the brake calipers and pads just because (unrelated to the moab incident). Everything is back together and I went to bleed the brakes and I have no brake pressure at all. I'm not sure what else could be wrong since I replaced everything that I could think of that was affected. Any help is appreciated!

 

[AuSeeker]

When you turn on the ignition and or depress the brake pedal do you hear the little electric pump motor on the master cylinder running?

If not then the motor could be shot or if you're lucky maybe a fuse or relay is bad, also check and be sure all the electrical connections to the master cylinder/ABS are connected properly or not damaged, sometimes tapping on the motor can get it working again if the motor is going or is bad.

If the motor is running correctly and especially if it runs for more than 15 to 20, 30 seconds then the pump portion could be shot and not building up hydraulic pressure, but I would think you still should be able to get a little bit of pressure just from the piston on the master cylinder.

Overall you seem to have problems with the master cylinder assembly, it could be several things that can cause it not to work, hopefully one of the above may be the problem and I hope it's a minor thing like a fuse or relay, or a connector loose.

 

[tellurunner]

When you turn on the ignition and or depress the brake pedal do you hear the little electric pump motor on the master cylinder running?

If not then the motor could be shot or if you're lucky maybe a fuse or relay is bad, also check and be sure all the electrical connections to the master cylinder/ABS are connected properly or not damaged, sometimes tapping on the motor can get it working again if the motor is going or is bad.

If the motor is running correctly and especially if it runs for more than 15 to 20, 30 seconds then the pump portion could be shot and not building up hydraulic pressure, but I would think you still should be able to get a little bit of pressure just from the piston on the master cylinder.

Overall you seem to have problems with the master cylinder assembly, it could be several things that can cause it not to work, hopefully one of the above may be the problem and I hope it's a minor thing like a fuse or relay, or a connector loose.

The ABS motor turns on and runs correctly as far as I can tell. I compared it to my buddy's truck which is exactly the same. I found a very small leak at the banjo bolt on the rear caliper but fixed that and still no brake pressure...

 

[riceandpho]

The ABS motor turns on and runs correctly as far as I can tell. I compared it to my buddy's truck which is exactly the same. I found a very small leak at the banjo bolt on the rear caliper but fixed that and still no brake pressure...

check all brake lines? the ones above the axle also the ones that run across the axle? seems like more air sill trap.

 

[tellurunner]

check all brake lines? the ones above the axle also the ones that run across the axle? seems like more air sill trap.

It seems that I just had a lot of air trapped in the lines and it took a lot of bleeding to get it out. Still doesn't explain why I started to lose my brakes and I blew up my axle but everything seems to work fine now.

 

[Bumbo]

If its air, perhaps if the master cylinder went dry, if so you might need to take it to the dealer to properly bleed the master with a SST?

 

[riceandpho]

It seems that I just had a lot of air trapped in the lines and it took a lot of bleeding to get it out. Still doesn't explain why I started to lose my brakes and I blew up my axle but everything seems to work fine now.

atleast you know your whole fluid is flushed out now. do you use a vacuum method or pressure method? or the old method where some one inside the car to pump brakes up.

 

[tellurunner]

If its air, perhaps if the master cylinder went dry, if so you might need to take it to the dealer to properly bleed the master with a SST?

Yep, I took it to a shop and they bled the system with the use of a scanner. Its quite possible air got into the MC.