dat620_77 Posted November 20, 2022 Report Share Posted November 20, 2022 Hello, I'm slowly rebuilding a 77 620 that has been sitting for almost 20 years. I'm starting with the brakes, and when testing the booster at the booster it won't hold vacuum. I need a new one. Last time I got one for a 73 I used to have, I got from rock auto no prob, now they don't exist. Does anyone know what is compatible? Thanks Quote Link to comment
datzenmike Posted November 21, 2022 Report Share Posted November 21, 2022 It's very small diameter to clear the clutch master beside it and the steering column below it. The 620 bolts to a spacer and the spacer bolts to the firewall. The 610, 710 and the S10 200sx all use the same small booster but not an exact match to the 620. Looks like the mounting bolts are longer and go through the thinner spacer to the inside of the cab. You may be able to swap the shorter 620 studs or shorten them but perhaps the push rod that connects to the brake pedal won't reach. I guess compare the overall length of the push rods and if it needs lengthening, cut and weld the 620 one onto the new one. I think this can be done with a little work. Quote Link to comment
dat620_77 Posted November 21, 2022 Author Report Share Posted November 21, 2022 Thank you Datzenmike!! You helped me a while ago with my 73 distributor switching from points to pertonix. I was hoping you would answer. However not the answer I wanted. I did see on ebay there is an adjustable pushrod. I think wilwood makes it. Does anyone know of rebuilders? Quote Link to comment
datzenmike Posted November 21, 2022 Report Share Posted November 21, 2022 Well the Datsun master vac push rods are threaded on the end and have spin on clevis and pin that's adjustable to set the pedal play. If the 610/710/S10s are shorter it may not be enough. Quote Link to comment
Stoffregen Motorsports Posted November 21, 2022 Report Share Posted November 21, 2022 23 hours ago, dat620_77 said: Hello, I'm slowly rebuilding a 77 620 that has been sitting for almost 20 years. I'm starting with the brakes, and when testing the booster at the booster it won't hold vacuum. I need a new one. Last time I got one for a 73 I used to have, I got from rock auto no prob, now they don't exist. Does anyone know what is compatible? Thanks You can have yours rebuilt. Power Brake Sales in Sacramento is who I send my boosters to for rebuild. https://powerbrakes.com/ 1 Quote Link to comment
dat620_77 Posted November 21, 2022 Author Report Share Posted November 21, 2022 2 hours ago, Stoffregen Motorsports said: You can have yours rebuilt. Power Brake Sales in Sacramento is who I send my boosters to for rebuild. https://powerbrakes.com/ Damn it!! I just moved from Modesto to Arkansas!! Cool I look into it. Thanks 1 Quote Link to comment
FrankRizzo Posted November 21, 2022 Report Share Posted November 21, 2022 My truck came with a 7" booster when I got it. I signed up for "alerts" on RockAuto when the correct 4 1/2" one came in - and it took about 3 months but as soon as I got the alert I jumped on it . But I did not need one immediately like you do.... Quote Link to comment
dat620_77 Posted November 21, 2022 Author Report Share Posted November 21, 2022 Thanks for all the help. As luck would have it there is an obscure little parts house in my town that says they can get one from their store in Tulsa. It'll be here Wednesday.🤞$130. Excanged 2 Quote Link to comment
Stoffregen Motorsports Posted November 22, 2022 Report Share Posted November 22, 2022 21 hours ago, dat620_77 said: Thanks for all the help. As luck would have it there is an obscure little parts house in my town that says they can get one from their store in Tulsa. It'll be here Wednesday.🤞$130. Excanged Beware that some booster suppliers use units that are close, but not exact. I've bought boosters that had holes welded up and new studs welded in for the application I needed, but they looked like crap. So don't surrender your booster until you see the new one. This is why I like having mine rebuilt. They rebuild the one I supplied to them. 1 Quote Link to comment
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