d510addict Posted February 3, 2011 Report Share Posted February 3, 2011 Anyone know if using a different master cylinder than the stock 521 M/C will improve the drums braking on a 1971 521? Quote Link to comment
datzenmike Posted February 3, 2011 Report Share Posted February 3, 2011 See about a vacuum booster (power brake) unit from a 620. It will lower the effort needed to work the brakes. Quote Link to comment
nismo dr Posted February 3, 2011 Report Share Posted February 3, 2011 wow that was mike's 17,000 post! :o keeping them adjusted is the best thing you can do, its amazing how well they work when they are adjusted correctly. Quote Link to comment
datzenmike Posted February 3, 2011 Report Share Posted February 3, 2011 True that! 10" drum X 4 brakes will get you stopped pretty good on a 2,700 lb truck. The problem is keeping them in adjustment. I had a 521 and (I never did) to keep it that way you would have to set them every 2 weeks. Quote Link to comment
nismo dr Posted February 3, 2011 Report Share Posted February 3, 2011 I let it go about six months, they go away gradually, adjusted them last week, almost put myself through the windshield! forgot how good they can be Quote Link to comment
izzo Posted February 3, 2011 Report Share Posted February 3, 2011 I let it go about six months, they go away gradually, adjusted them last week, almost put myself through the windshield! forgot how good they can be Damn really? mine need to be adjusted on the 521. Seems like they work ok if i press harder. I'd like it to stop a bit better tho. I hate adjusting the drums. Guess i should do it, one day ;) But gotta work on the dime first! Quote Link to comment
wayno Posted February 3, 2011 Report Share Posted February 3, 2011 I have a question guys, can the backing plates on a 1984 nissan 720 with all the hardware and the automatic adjusters be bolted on a 521 rear axle housing? You would run the 84 720 brake drums also. Quote Link to comment
datzenmike Posted February 3, 2011 Report Share Posted February 3, 2011 Don't quote me on this but there is, but I believe, an axle difference between self adjusting and the earlier 720 axles. The self adjusting and longer. On top of that 720 axles are longer than 521 so you can't just put 720 axles with adjusters in the 521. Quote Link to comment
]2eDeYe Posted February 3, 2011 Report Share Posted February 3, 2011 wow that was mike's 17,000 post! :o keeping them adjusted is the best thing you can do, its amazing how well they work when they are adjusted correctly. ... and the best way to keep up on them, I've found, is to adjust every other oil change. Quote Link to comment
d510addict Posted February 4, 2011 Author Report Share Posted February 4, 2011 Sweet TY looks like I will be taking the drums into the shop to get turned a bit as they are old as hell and doing some adjusting. Quote Link to comment
mysterymojo Posted March 2, 2011 Report Share Posted March 2, 2011 True that! 10" drum X 4 brakes will get you stopped pretty good on a 2,700 lb truck. The problem is keeping them in adjustment. I had a 521 and (I never did) to keep it that way you would have to set them every 2 weeks. I would imagine the brakes on the 521 and the 620, which is what i have, are almost the same or very similar. What you said about adjusting for the 521, adjusting for the 620 brakes would probably help fix this problem too right? mine are very abrupt right now. if i push down on the pedal a little, nothing happens, if i push down just a little more with normal pressure from my foot, they lock up and i skid. lol. this hardly seems normal. i have to baby the pedal very slowly not giving it too much pressure but just the right amount to stop slowly. Im too scared to drive over 30mph. maybe bleeding the brake lines or having the inside of the drums milled a little to clean the surface as well? any suggestions of what I could or should do to get the brakes working better? Quote Link to comment
datzenmike Posted March 2, 2011 Report Share Posted March 2, 2011 I would bleed them fully replacing all the fluid from the master back. Most of the braking effort is done by the fronts with maybe 20% to the rears. Because of weight shift to the front they are harder to lock up the rear becomes lighter and are easier to lock. If your fronts are mushy the rears will have to work harder and will lock easier. Quote Link to comment
Rob W. Posted March 2, 2011 Report Share Posted March 2, 2011 I have never owned anything besides an old International Pick-up that had drums all around until now. Mine are ok but I just found out what I'm doing tomorrow seems like an easy thing to do that would make a big drivability difference. Man this forum is too cool! Oh and duh should of snapped to this just so used to discs up front that I never really thought about it. Quote Link to comment
mysterymojo Posted March 2, 2011 Report Share Posted March 2, 2011 I would bleed them fully replacing all the fluid from the master back. Most of the braking effort is done by the fronts with maybe 20% to the rears. Because of weight shift to the front they are harder to lock up the rear becomes lighter and are easier to lock. If your fronts are mushy the rears will have to work harder and will lock easier. that's a good point. Ill probably do that first and see if it makes a difference. Quote Link to comment
d510addict Posted March 8, 2011 Author Report Share Posted March 8, 2011 Hmm anyone in Portland/Milwaukie area have a good idea on getting drums off that are seized onto the hubs? Mallet didn't work and I do not want to ruin them. Quote Link to comment
DanielC Posted March 8, 2011 Report Share Posted March 8, 2011 They can be a real "female dog" Make sure the adjuster is retracted all the way. Spray penetrating oil into the lug nut holes, and around the center hub. Hit it some more. Quote Link to comment
datzenmike Posted March 8, 2011 Report Share Posted March 8, 2011 Look on the drum there are two small threaded holes across from each other. Get a bolt that threads it (don't know the size) tighten in alternately and the bolt bottoms against the axle. Keep going and it levers the drum out and off. First loosen the emergency brake cables and back the star adjuster off to retract the brake shoes. If the shoes are not retracted the drum will rip them off and the anti rattle springs. Quote Link to comment
wayno Posted March 8, 2011 Report Share Posted March 8, 2011 Hey Datzenmike, the 521 didn't have them metric threaded holes. All I have done in the past d510addict is hit the drum and axle harder, I gave up on the 521 3rd members for the most part, pain in the ass, I run 720 running gear anymore with stock 521 rims and caps. I guess I should mention that I am not currently running any 521s with the stock box, there all currently either flatbed or stepside boxes. wayno Quote Link to comment
Figbuck Posted March 10, 2011 Report Share Posted March 10, 2011 I made a rear drum puller out of 1" X 2" piece of box section tubing and some all thread. If backing off the adjusters, screwing a couple 10mm bolts and beating the hell out out the drums with a 5lb single jack doesn't get them off... PM me. I'm near SE Main St. and MLK near the east end of the Hawthorne... you can borrow it. Quote Link to comment
DanielC Posted March 10, 2011 Report Share Posted March 10, 2011 Can you take a picture of your drum puller, Please? Quote Link to comment
mklotz70 Posted March 20, 2011 Report Share Posted March 20, 2011 If you're sticking with stock drums, I would at least upgrade the m/c to a '77 620 dual reservoir m/c :) You may need to heat the drum up with a propane torch to break the rust loose. Quote Link to comment
zenndog Posted March 24, 2011 Report Share Posted March 24, 2011 I switched my 320 to the 620 dual master, it is a safety thing. I have had two single masters fail and I won't drive a car with a single master. Here is my brake thread (with part #'s) from days long past, Brakes still work great, but they do need adjusting often. Many of the parts I ordered for my 320 were 520 parts I think. The only thing that wasn't right was one of the axle seals. http://community.rat...rakes-overhaul/ Oh, one word of warning. The Dorman springs were crap, two springs failed, so keep the old parts around. I ended up needing two of the old springs because two new ones broke. Quote Link to comment
68Datsun510 Posted March 24, 2011 Report Share Posted March 24, 2011 A large ball peen hammer strike just outside the lug circle should work. Hit it like you mean it!!! Quote Link to comment
d510addict Posted March 24, 2011 Author Report Share Posted March 24, 2011 Alright I'm going to try some of these things, hopefully I can get these fuckers apart as my brakes blow and are randomly catching leading my car to yank to 1 side during hard braking (although it doesn't always catch just some times). Quote Link to comment
d510addict Posted April 3, 2011 Author Report Share Posted April 3, 2011 Mike what bore is that M/C, or does it only matter if its the verticle tab + front and back drums on the donor? 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.