lynchfourtwenty Posted July 21, 2007 Report Share Posted July 21, 2007 just wondering if the 79 620 m/c would be a direct bolt into my 77 620.. im going to be doing the disc brake conversion really super soon and i want to know if i need to get a new m/c or if the old 4 drum one will work, i believe i've been told it doesnt work properly for reasons i cant put into words.. anyways i want to do as little modding as i have to since i dont really have the tools to doit with.. so will the 79 620 front disc rear drum m/c bolt directly in and work the way i want it to?? or is there something else i should use ??? Thanks a ton as always guys! Quote Link to comment
SHADY280 Posted July 21, 2007 Report Share Posted July 21, 2007 the 4 wheel drum one wont work, it has different valving on it to keep pressure on the cups in the operating cylinders, best to used the one from the 78/79, thats what i am doing on mine. there may be better upgrades, but im going half original. Quote Link to comment
lynchfourtwenty Posted July 21, 2007 Author Report Share Posted July 21, 2007 well thats kinda my plan to.. i dont need it to be like nascar an shit.. i just need something more efficient that the 30 year old drum design.. known fact: datsun 4wheel drum brakes SUCK! haha so is there any shaft modding needed? i notice some m/c's peopleused they had to extend or shorten the shaft or put the old end on or whatever... is it direct bolt in no mod.. man i ramble.. sorry guys Quote Link to comment
SHADY280 Posted July 21, 2007 Report Share Posted July 21, 2007 that part i dont know, i figured i would read it somewhere, or someone who has done it would chime in! dont ya hate it when ya dont know if your shaft is gonna work? Quote Link to comment
BEEBANI Posted July 21, 2007 Report Share Posted July 21, 2007 The '79 will bolt right in. The only mods were for the 521 guys. Quote Link to comment
lynchfourtwenty Posted July 21, 2007 Author Report Share Posted July 21, 2007 ok thanks man thats just the info i needed :) Quote Link to comment
datzenmike Posted July 21, 2007 Report Share Posted July 21, 2007 The drums are only pretty good when they are constantly kept properly adjusted, which is never. Josh, when you swap in the '78-'79 you are also increasing from a 3/4" to a 13/16" bore m/c. Which is a good thing too. Quote Link to comment
lynchfourtwenty Posted July 21, 2007 Author Report Share Posted July 21, 2007 oh cool, as long as its better then what i've got now i'll be happy i called the local part stores and a combanation of 2 im able to get all the parts i need for $250 basicly gettin the m/c, brake lines, "loaded calipers" so that even includes pads and then im gettin rotors from another place cause they're like $40 cheaper haha :) so yea when i get paid i should be able to get this swap done.. Oh the brake lines that goto the m/c will line right up right?? Quote Link to comment
datzenmike Posted July 22, 2007 Report Share Posted July 22, 2007 To be honest I don't know.. at a guess I would say probably, yes. Did you get new front flex lines too? I had a 521 drum brake and it would dart all over the road on hard stops. The adjuster would snap off at the mounting clip, or it would be frozen and there was no easy way to get it perfect and have it last for more than a couple of weeks. Never had any problem on my '78 (no adjusters, lol) maybe a slight leak, had a spare, threw it on, bled it and kept going. I converted my '68 dime to dual m/c 'back in the day' the stock lines were 'bubble' flair and the new m/c was 'double reverse'. (or something) Anyway I hand filed a taper on the flairs and tightened them on and it worked like a hot damn!! Somehow I survived and am here to tell you to make sure that anything you do to your breaking system is the right way, the first time!! Quote Link to comment
lynchfourtwenty Posted July 22, 2007 Author Report Share Posted July 22, 2007 HeHe, sounds like fun??!! haha yea im getting new lines to go from caliper to hard line.. the hard line one i just slip the rubber one over and use a hose clamp to tighten it on right?? cause im gunna use the brake lines for the 97 hard body calipers.. so they should also fit right up right.. and as for "Darting all over the road" its sooooo much fun!!! NOT! usualy only does it when cold tho i've adjusted them and it doesnt seem to help much really the adjusters work they're not frozen or broken but i think they're adjusted as it gets.. so yeah like i said when i get paid im switchin these things hopefully it goes nice and smooth Quote Link to comment
lynchfourtwenty Posted July 22, 2007 Author Report Share Posted July 22, 2007 OH one thing i've been wondering.. do i place the caliper so its infront of the wheel behind the bumper or behind the wheel infront of the door??? if ya know what i mean.. i've noticed it can go either way.. i just want to doit the right way Quote Link to comment
datzenmike Posted July 22, 2007 Report Share Posted July 22, 2007 The factory put them toward the rear. If you swap sides they might go on the other way but the flex lines may not reach or be damaged on a full lock turn. They might even rub the control arm or some other suspension part. Quote Link to comment
lynchfourtwenty Posted July 22, 2007 Author Report Share Posted July 22, 2007 so tword the rear it is then Quote Link to comment
datzenmike Posted July 22, 2007 Report Share Posted July 22, 2007 Most vehicles have them to the top rear. They would work fine upside down even. All I can see is that there is less road spray and dirt in this position, less chance of being dipped into a puddle and they are easy to reach. Quote Link to comment
OL YELLER Posted July 22, 2007 Report Share Posted July 22, 2007 Can I Please just add my 20 cents to the mix here?...I have been driving for more years than I care to remember...(Hell it ain't that long...got my Lic. in 1956!)...anyway, let me go on...ALL of the automobiles I owned UP to the new 79 GMC pickup I bought had 4 wheel drum brakes....including of course my two original Datsuns (76 620 (original "Ol Yeller) and a 72 510 wagon)..anyway to my point...I have not had much problems with any of my drum brake cars or trucks...NOW comes the caveat!...I have always maintained my vehicles in the same general manner...oil changes at 3000 miles, etc...AND each time I would check and readjust the brakes as needed or if needed...now granted the early Datsun brakes are in a word..AWFUL...but, having said that, they were adequate for the application they were intended for....I am sure that given the right set of circumstances all brakes suck if you don't use them correctly or if you don't remember that this is not a race car we are talking about...at 65-70 miles an hour..these brakes will do an adequate job of bringing the truck to a halt......I am not in any way saying that the idea of putting newer brakes on the older trucks is a bad one..what I am trying to say is that in "the day" the stock brakes worked just fine......(Think about this: in 1957 Chevrolet had a 270 horsepower fuelinjected 2 door hardtop with DRUM BRAKES.....hmmmmmmmmmmmmmm (wait was the fuelie a 283 horsepower and the dual quad version 270 horse....ah never mind...anyway you get my point? Quote Link to comment
datzenmike Posted July 22, 2007 Report Share Posted July 22, 2007 Yes they would stop you and were adequate for the job for sure. The discs did the same (or slightly better) and were maintainance free and easy to replace/work on. I think it was 283 hp and even scarier was the single piston m/c. Quote Link to comment
OL YELLER Posted July 22, 2007 Report Share Posted July 22, 2007 well that is kinda what my point was...the original braking system for most cars are adequate for the type of car they are on....remember an awful lot of the early "Muscle Cars" were mostly drum brake systems...anyway, just a thought...I know that my 73 brakes work very nicely thank you LOL....(most of the American cars were single piston M/C, right?.....seems to me that one of the selling points the dealer said about my 72 510 wagon was the dual brake lines....I seem to remember them going on and on about that very fact.....(see the OLD memory isn't too bad.....YET!) Quote Link to comment
datsun dreamer Posted July 22, 2007 Report Share Posted July 22, 2007 I would agree i've had "older" classics such as a 1948 Chevy fleetmaster a real heavy car for its time and the drums worked very well as long as they were properly maintained,disc brakes are definately alot less maintanance(imo)but both are very good systyms and do their job nicely!(as long as u r obeying california speed laws!LOL!!). Quote Link to comment
lynchfourtwenty Posted July 22, 2007 Author Report Share Posted July 22, 2007 well lets just say the ol'lyncher doesnt obey speed laws and needs to come to a stop in a hurry! MY brakes dont do me any good.. im sick and tired of VERY QUICKLY down shifting just to make sure i dont hit the person infront of me... not to mention the first few times i use my brakes in the morning it likes lunge me to the right as if it were posessed.. im sure in they're day if used the way they were intended worked fine... however for me.. they do not work fine and i'd much rather have maintenece free brakes that i can change the pads on in 10 mins, thanks for the replys guys :) Quote Link to comment
]2eDeYe Posted July 23, 2007 Report Share Posted July 23, 2007 When mounting your calipers, make sure your bleeder screw is to the top of the caliper. This allows the lighter air to go to the top of the cylinder and out the bleeder screw as you bleed the brakes. Quote Link to comment
datsun dreamer Posted July 23, 2007 Report Share Posted July 23, 2007 Hey lynch, That was funny! But after reading that i think it's safe to say it's a safety issue and your truck should get disc brakes! As far as your truck being possesed I'm sure the forum will pray for your truck!LOL!!!!!!!Let us know how it turns out!!!!!!!!!! Quote Link to comment
Glengemen Posted July 23, 2007 Report Share Posted July 23, 2007 HeHe, sounds like fun??!! haha yea im getting new lines to go from caliper to hard line.. the hard line one i just slip the rubber one over and use a hose clamp to tighten it on right?? cause im gunna use the brake lines for the 97 hard body calipers. Yeah, about those hose clamps on your brake lines very very bad idea, as you will blow the soft line as soon as you try to stop. You have to thread your line ends together with the fittings already there. Lucky that Datsun and Nissan use the same fittings so no modification needed. Also as far as mounting the caliper it will need to go to the rear as your steering arm and caliper have to be on opposite sides, and you will have a hell of a time putting the tierods to the rear. Hope that helps:D Quote Link to comment
lynchfourtwenty Posted July 23, 2007 Author Report Share Posted July 23, 2007 awesome! good info guys these are very helpful tips Much appriciated and i've never replaced a brake line so as for the "fitting" i wasnt sure what it looked like.. suprised i've never checked one out.. well i will now! dreamer, im like a clown :P Quote Link to comment
datzenmike Posted July 23, 2007 Report Share Posted July 23, 2007 Yeah, about those hose clamps on your brake lines very very bad idea, as you will blow the soft line as soon as you try to stop. You have to thread your line ends together with the fittings already there. Lucky that Datsun and Nissan use the same fittings so no modification needed. Also as far as mounting the caliper it will need to go to the rear as your steering arm and caliper have to be on opposite sides, and you will have a hell of a time putting the tierods to the rear. Hope that helps:D Wow missed that!! Josh I have a FSM for the 84 720 and there's a graph showing that a pedal pressure of 132 lbs produces a rod pressure of 529 lbs and with the vacuum boost the hydraulic line pressure can exceed 1,962 lbs!!!! No gear clamp made will hold that! I've made panic stops where my ass lifted off the seat and I almost tore the wheel off the column so 132 lbs on the pedal is easy to do. Quote Link to comment
lynchfourtwenty Posted July 23, 2007 Author Report Share Posted July 23, 2007 yea, like i said i havent had to change brake lines on anything ever so i've never really delt with them, im just makin sure all the parts im buying are going to work properly.. but if they just kinda screw in an theres no differences then it should be all good :) Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.