2010 LR4 brake bleed question

[Mozambique]

I read somewhere that bleeding brakes on an LR4 requires the engine to be running (something to do with the brake power booster) - correct, or is that not necessary. Anything else I should know beyond bleed from farthest location to nearest?

Thanks in advance!

 

[Quijote]

I bled my brakes the old fashioned way with the engine off. No problems.

 

[avslash]

I bled my brakes the old fashioned way with the engine off. No problems.

Ditto

 

[Krill]

I do it with it running, have done it in the past with it off don’t really think it makes a difference( unless you’ve got your girlfriend pumping the pedal....then do it with it running so it’s easier to push)

 

[gsxr]

Does anyone know why the LR4 FSM requires pumping the pedal even if using a pressure bleeder? Usually, pressure bleeding eliminates the need for pedal pumping. Seems bizarre to me. I have used a pressure bleeder on my other vehicles for 15+ years and never needed to touch the pedal - and, it's a 1-person operation.

 

[Quijote]

That doesn't make sense. It should be one or the other.

 

[sceh]

Equally odd is that the FSM says to press the brake pedal down 2/3 of it's travel and then let it come back up for 1/3 of it's travel.
Why?
I have always done it with full travel down and up. The FSM also says you need to do this 28 times for each back brake..!
Any ideas or should I just do it the normal way and without the engine running?

 

[gsxr]

It generally isn't recommended to press the pedal to the floor when bleeding. The reason is, during normal operation the pedal never gets past 1/2 to 2/3 of travel in the master cylinder, and over time a ridge can build up around that point in the cylinder. When you push it past the ridge during bleeding, it can damage the seals and require either rebuilding or replacing the MC. A lot of old / high-mile MC's have died from bleeding. Generally you want to only push half-way down.

Now, the part about only letting the pedal come up part-way... never heard that before. No idea why that would matter. I've always used pressure bleeders in my other vehicles which eliminates the need to touch the pedal.

 

[ktm525]

I used my mity vac and some aquarium tubing attached to the caliper bleeders with no issue (suction). I used 1L of Pentosin Dot IV LV to replace the fluid at all four corners.

 

[sceh]

I have a Mityvac. So, you simply attach it to the bleed nozzle and suck? What if there is air in the master cylinder? I assume you woul do this with the brake pedal fully depressed?