izzo Posted January 13, 2009 Report Share Posted January 13, 2009 Ok. So when i am cruising down the street, and i apply the brakes. They do like a pulse. It is as if I am tapping the brakes over and over. The faster i go the faster it happens, the slower i go the slower it happens. And if i am near stop and i use to much it will lock one tire up in the front. Keep in mind when this happens, the steering wheel does not go left and right when this happens. Just like i tap the brakes... What is your input? My thoughts are that the rotors need to be turned. I wanted to know if everyone else thinks that too. Other possibilities i thought of were maybe sticky calipers but it wouldnt pulse like that. Also thought maybe a slight vacuum leak, but again i wouldnt think it would pulse like that. Schucks charges only 10 dollars a rotor to turn them, but there's none around here so i have to do it at schwabs for 20 a rotor.. So i am double checking others inputs and thoughts before spending hte money and having it be something else. The break fluid is full and I dont see any leaks. Quote Link to comment
datzenmike Posted January 13, 2009 Report Share Posted January 13, 2009 Pop the wheels off and sand the rotors with sand paper. Use a circular motion or an electric sander if you have one. Don't forget the back side. Don't worry it will take a lot of sanding to cause a low spot. What has probably happened is you have used the brakes hard at some time and allowed the truck to stop and sit. Material will transfer from the pad to the very hot metal rotor and leave a 'foot print' on it. This happens most easily when new pads are put on. Now as the rotor turns the friction material scuffs over the friction material baked onto the rotor and binds. Doesn't take much, you may even see an imprint on the rotor. The best way to 'break in' new pads is to go out on the highway an get up to speed and apply the brakes hard and slow to 30 then speed up and repeat. The idea is to heat up the pads and boil off the excess resin that bind the friction material together. Do not stop for a moment while the pads and rotor are hot or material will transfer. Continue driving until cooled down. New pads can be on for months and a sudden application of brakes or overheating while towing a trailer, and suddenly the braked thunp when you use them. Turning them will fix the problem but it can come back again. Bit of bother but cheap fix if it works. Quote Link to comment
izzo Posted January 13, 2009 Author Report Share Posted January 13, 2009 Sounds good mike. I will give it a shot, Sand paper is cheap and i have a couple sanders laying around i could use. sand paper is only 2 or 3 dollars so i will give that a shot on thursday. Thanks for the tip. I understand what you mean. I will take some pictures and post before and after. Quote Link to comment
yello620 Posted January 13, 2009 Report Share Posted January 13, 2009 Or you could save yourself all that extra labor and just get them machined and be done with it. I think that most Napa's can do them too. Think my local napa is only 15 per rotor. Quote Link to comment
ggzilla Posted January 13, 2009 Report Share Posted January 13, 2009 Schucks charges only 10 dollars a rotor to turn themMan that's cheap. Another possibility: if your rotors are warped it can cause a pretty violent shaking, often worse on slight downhills. '80s Fords are notorious for this, but it happens to other brands too. Not heard it happening much with Datsuns though. Solution is to turn the rotors. Quote Link to comment
izzo Posted January 13, 2009 Author Report Share Posted January 13, 2009 Sounds good. The local napa doesn't turn rotors here, only place is schwab. I called around to some shops and asked, les schwab is by far the best price. Other places were charging 75 DOLLARS to run rotors. are you kidding me? for that amount i can just buy new ones... Think i will just have them turned, and keep in mind what mike had said. Quote Link to comment
izzo Posted January 15, 2009 Author Report Share Posted January 15, 2009 OK. Havent had a chance due to work :( Its nice as hell out too... Anyways, i noticed the front end doing the pulsing and at least catching the other day, it was wet out. I drove it last night, nice and dry out. It could very well be the back end drums being warped. I stopped at a stop light and the back driver side tire locked up. blah... if the drum was warped, only option is to replace it right? Quote Link to comment
datzenmike Posted January 15, 2009 Report Share Posted January 15, 2009 (edited) Or have them turned. Old Dodges were notorious for being 'grabby' when damp or in the rain. I used to drive a block with my foot resting on the brake to warm them up. Maybe similar on yours. Might depend on the shoe used and could even be damp from leaky wheel cylinder? Back end lock up is common on our trucks, more so in the rain. Weight shifts forward off the rear wheels when braking and rear wheels need very little brake effort to lock up. The tire that did may just be adjusted a bit tighter than the other side. Not sure about the 521 but the 620 (disc brake) has a load sensing device. Empty, the rears should not lock on dry pavement before the fronts. With a load, more pressure is allowed to the rears. Note, this is for DRY pavement, wet... all bets are off. Edited January 15, 2009 by datzenmike Quote Link to comment
lynchfourtwenty Posted January 16, 2009 Report Share Posted January 16, 2009 my se-r (all wheel disc brakes) does that tapping vibrate thing also... i put new rotors an brakes on it an it still does it... however i did change the rotors an brakes a different times (front then back) but i dont think they're warped or nothin i think what mike was explaining is what prolly happend... never had any problems on any other cars before.... OH an my new se-r when i got it didnt do that.. but when i swapped the brake systems from my wrecked one to the new one it started doin it.. i just didnt want 4 new calipers/rotors/pads goin to waste.. it stops fine i've never had a problem there.. i think when it comes time for new brakes i will do all of them at once plus i will have the rotors turned or buy new ones since they're so cheap.. i think its like $15 - $20 for rotors .. but since they are kinda new i'll prolly jus have em turned Quote Link to comment
yello620 Posted January 16, 2009 Report Share Posted January 16, 2009 my se-r (all wheel disc brakes) does that tapping vibrate thing also... i put new rotors an brakes on it an it still does it... however i did change the rotors an brakes a different times (front then back) but i dont think they're warped or nothin i think what mike was explaining is what prolly happend... never had any problems on any other cars before.... OH an my new se-r when i got it didnt do that.. but when i swapped the brake systems from my wrecked one to the new one it started doin it.. i just didnt want 4 new calipers/rotors/pads goin to waste.. it stops fine i've never had a problem there.. i think when it comes time for new brakes i will do all of them at once plus i will have the rotors turned or buy new ones since they're so cheap.. i think its like $15 - $20 for rotors .. but since they are kinda new i'll prolly jus have em turned When i have to install new rotors on anything at work, the new rotors ALWAYS get turned before installing them. They are usually slightly warped. New rotors are supposed to be stocked flat, not on edge in the boxes. But due to most warehouses and parts stores not caring they stock them on there edge because it takes up less warehouse space. This causes the new rotors to be a warranty problem when brand new if not machined. Quote Link to comment
izzo Posted January 21, 2009 Author Report Share Posted January 21, 2009 (edited) Got the drums turned. It still a wobbles a little bit up front but ill turn those on friday. There is plenty of pad left on the back brakes, but i dont think they are adjusted right. the wheel cylinder is at the top, and i think the adjust screw is at the bottom, is this right? I seen a smaller cylinder looking item at the bottom so i looked around on the net. What i found was 2 different things. One was the second cylinder at the bottom of the wheel you could adjust, or there was a rubber cover on the back of the backing plate you could take off, and adjust somehow that way. However, when i looked i didnt see how to adjust it either way. I know about how much to tighten the shoes, just now how. Any suggestions? also pls see second picture, i went to pull the front discs off, but the entire hub came with it. Is it supposed to come apart?? From the pictures i saw of the new disc rotors at autozone/napa etc i dont see how it would fit on there... all the other cars i have done brakes/rotors on, you just pulled the caliper off and then the rotor slid off Edited January 21, 2009 by h2theizzo Quote Link to comment
sliding_creep Posted January 21, 2009 Report Share Posted January 21, 2009 how are your front wheel bearings or suspension bushings. these will also lead to irregularities in braking. was the castle-nut tight, pin still thru it? did you lift the vehicle and grab the top and bottom of tire and shake to see if theres play? how are the rear axle-bearings? (truck, right?) i've seen quite a few cars get all new everything and still do the same wobble or hula-dance due to a little detail* that was missed. cheers *(ie: theres a dumbarse on this site that forgot to expand his brake pushrod!) Quote Link to comment
510er Posted January 21, 2009 Report Share Posted January 21, 2009 get one of these Quote Link to comment
izzo Posted January 21, 2009 Author Report Share Posted January 21, 2009 get one of these lol... cute, I have Alldata and Mitchel On demand, however it doesn't go over this to well is why i ask so many ?'s Quote Link to comment
izzo Posted January 21, 2009 Author Report Share Posted January 21, 2009 with that said, i bought it. 14.95 for the manual, not to bad. I will take a look at it once i get the book. I checked the Bearings when i jacked it up, they seemed fine. I did notice the steering was a tiny bit loose, when the time comes to tighten that up i will post in the other sections. Date: 01/21/2009 17:47:02 CDT http://discountautorepairmanuals.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=darm&Product_Code=B72030-97&Category_Code=D Thank you for ordering from Discount Auto Repair Manuals! Thank you for your order. Orders will be shipped within two business days from California. U.S. orders are shipped either USPS priority mail or USPS media mail depending on the option selected. Priority mail (Air) takes 3-7 days and media mail (ground) takes 10-21 days for delivery. Hawaii, Alaska, and US territories may take longer. All orders to Canada are shipped via USPS airmail and will take 7-10 days for delivery. For changes to this order please email us at websales@discountautorepairmanuals.com We no longer accept check payments. Quote Link to comment
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