73 smurf 620 Posted April 6, 2012 Report Share Posted April 6, 2012 So i have replaced the booster, master cylinder, rebuilt all the wheel cylinders, bled all the way around, bench bled the master, and shoes all the way around. The problem is I have no pressure when the truck is running, the pedal goes to the floor. When it is off, an when the vacuum line on the booster is removed is removed there is tons of pressure but the brakes still don't work. Any advice or suggestions. Quote Link to comment
I'm BLUE Posted April 6, 2012 Report Share Posted April 6, 2012 *booster check valve replacement *master cylinder to booster rod adjustment ( what did you set it at? ) *all shoes adjusted correctly 100% and double checked? * leaky line/bad rubber line? ( hope wheel cylinders were honed ) *** lastly ... sometimes re manufactured products come "bad" ... if all else fails ... after double checks keep this in mind. Could you clarify last sentence please? Quote Link to comment
73 smurf 620 Posted April 6, 2012 Author Report Share Posted April 6, 2012 When the truck is not running, it has a lot of pedal pressure. As well as when the vacuum line is pulled off of the booster and plugged, there is a lot of pedal pressure. But if the truck is running, and the vacuum line is on, it has no pedal pressure. Quote Link to comment
datzenmike Posted April 6, 2012 Report Share Posted April 6, 2012 Adjust the shoes closer to the drums. Raise each wheel and spin tire by hand while tightening the start wheel. When you can't turn the wheel pump the brake to center the shoes in the drum and check and adjust some more if needed. It's considered adjusted when you can feel resistance to turning by hand. Move to the next wheels. Did you bleed the NLSV? It's on the inside of the frame under the pass side seat. Quote Link to comment
73 smurf 620 Posted April 6, 2012 Author Report Share Posted April 6, 2012 NLSV? No I did no, never saw it. I will try that today. Quote Link to comment
datzenmike Posted April 6, 2012 Report Share Posted April 6, 2012 Nissan Load Sensing Valve. I think there are 3 bleeder valves there. Bleed in this order... MC front MC rear NLSV front front wheels rear wheels (left first) NLSV rear NLSV center Quote Link to comment
metalmonkey47 Posted April 7, 2012 Report Share Posted April 7, 2012 Mike, were all 620 equipped with the NLSV? Quote Link to comment
73 smurf 620 Posted April 11, 2012 Author Report Share Posted April 11, 2012 Well, everything bled fine. But still no stop, I'm convinced it need new wheel cylinders. Quote Link to comment
datzenmike Posted April 12, 2012 Report Share Posted April 12, 2012 Mike, were all 620 equipped with the NLSV? I always assumed so but looks like '76 and on had them. Quote Link to comment
Viico04 Posted May 9, 2012 Report Share Posted May 9, 2012 Im also having the same issue with my truck. Any one got a picture on the nlsv? Quote Link to comment
metalmonkey47 Posted May 9, 2012 Report Share Posted May 9, 2012 Mike it appears the '76 wasn't equipped. I checked every inch of brake line and didn't find anything other then brake line unions. Nothing with a single bleed screw. Quote Link to comment
datzenmike Posted May 9, 2012 Report Share Posted May 9, 2012 It may have just been the earliest one. There were long and short beds and KC.... maybe only on the KC? Quote Link to comment
620Soldier Posted May 18, 2012 Report Share Posted May 18, 2012 Great thread. My brakes are a bit on the soft side myself, but I'm pretty sure I just to get those new shoes on there. Lots of good things to know in this thread, thanks a bunch. Quote Link to comment
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