Radim Posted March 30, 2010 Report Share Posted March 30, 2010 Let me introduce myself since this would be my first technical post.. My name is George im from Orange County, CA... I just recently bought a 73 630, and the brakes are extremely iffy. There is no power at all to the front brakes, and the brakes cause the engine to want to stall which is obviously a vacuum problem. There is a line under the first reservoir that isn't hooked up. The first of the two(top to bottom) I searched through the FSM but couldn't really see where the hose went. Would be great if someone posted a detailed pic of the BB Vacuum lines. This line should be causing both problems, right? Quote Link to comment
I'm BLUE Posted March 30, 2010 Report Share Posted March 30, 2010 Welcome to Ratsun :cool: Does your 620 have a power brake booster ? If so , look for the black check valve inline from the engine to the brakes , or a leaky booster to start with ? Do you have any pictures ? ( First rule of Ratsun Pics or go home :lol: ;) ) This will help others help you if possible , might be someone jerry rigged the thing IDK ? hope that helps start things off a bit ! Quote Link to comment
Radim Posted March 30, 2010 Author Report Share Posted March 30, 2010 Hehe, i left the computer just after i posted to take this pic for you guys. :) Quote Link to comment
datsunaholic Posted March 30, 2010 Report Share Posted March 30, 2010 Those unhooked lines aren't for the brakes. That's the evaporative emissions system, pulls fumes in from the gas tank back to the manifold. The one not hooked up goes to the air cleaner. The Vacuum booster has ONE and only one connection- big hose from the booster to the intake manifold, and should be clamped to the firewall in the middle. This is a '75, but the brake booster hose is very obvious in this pic. But if you get stalling when you hit the brake pedal, then the booster has a hole in it. You will have to replace it. But word of caution- there are a couple designs out there and later model ones won't mount to the firewall the same way. I think even my '74 one was different. Quote Link to comment
Radim Posted March 30, 2010 Author Report Share Posted March 30, 2010 Thanks for the good and bad news. :) I guess i'll just replace it. Quote Link to comment
Pacific coast Datsun Posted March 31, 2010 Report Share Posted March 31, 2010 My 74 had the same issue. It was a bad brake booster. I replaced with one off a 78 620. Quote Link to comment
Radim Posted March 31, 2010 Author Report Share Posted March 31, 2010 Awesome! Thanks for the input! Quote Link to comment
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