It's OK, Koffietje, I wonder how we'd all do using your language. Probably not as well, to say the least. Amerikaner is a tough second language, it's even hard if you're born to it.

I would say a brake bleed would be the first priority,steph66, then be sure your power brake booster is hooked up.

Now, do you have the grinding noise ONLY when you use the brakes?(it could be the sound of air bubbles in your lines) Or all the time as you drive?

 

So I haven't replaced the master cylinder/vacuum booster yet but when I took the truck out for a drive and pushed on the brakes it is still making that grinding noise????? Could it be to do with the master cylinder? Should this go away after I replace it? Does the grinding noise mean that the brakes aren't working cause the master cylinder/vacuum booster is shot or could this be a different thing all together??? Please could someone give me some solutions to this. Thanks

The grinding noise is only when I push on the brakes.

 

The grinding could also be something not put back in the right place, you may need to pull the wheels, have some one work the peddle and look at how and where the calipers are working and how the pads are contacting the rotor.
If the rears are drums, pull the drums and check for gouging on the inside.

 

do not press on the brake with the drums off, the cylinders can over extend without the drum to prevent extended movement.

 

I was curious if I had to bleed the isolation dump valve as well as all 4 brake lines after replacing master cylinder?????
is it absolutely necessary to bench bleed the master cylinder or can you just keep bleeding the brakes?

 

Thats odd I am pretty sure I responded to this post this morning ?!?
It is best to bench bled the master cylinder as it is a whole lot easier to do on the bench then trying to bleed out on the vehicle. Air in the system is the brake systems worst enemy...