Sunrader John Posted July 9, 2011 Share Posted July 9, 2011 In 2009, I bought a Toyota RV with 50,000 miles that was built on a 1986 one ton pickup with the 22RE engine. This winter I had all the brakes serviced (new pads, usual cleaning of parts but no other replacements). The front are disc brakes, the rear are drum brakes on dual tires (each side). Since then, the brakes act normal to a moderate amount of brake pressure, but if I have to put more pressure quickly, the front tires will lock up, leaving smoke and skid marks. Most of the time it pulls to the right, but it depends on what tire locks up first. What would cause this? The mechanic just said it was working now like it should, even though for the 1 and 1/2 years I owned the RV before the brake jobs, it braked just fine. Now I believe it is dangerous, as I might not be able to stop quickly in an emergency. When the road is slippery or is gravel it feels like it skids even sooner. Could it be a LSPV not functioning correctly? The previous brakes were asbestos, the new ones organic- could that cause it? The rotors were turned, though the mechanic said this was the last time they could be turned. According to my cousin, who has done several brakes over the years, the rotors are fine. On the very top edge there is a slight roughness, but my cousin thinks it is minimal and doesn't affect the braking. Also, it's been over six months since the brake job, so the pads have to be worn in by now. Why would it be ok before a brake job but not after? The mechanic said the rear brakes had not been changed in a long time (if ever), but still had some wear left on the pads when he replaced them. Thanks for comments. Quote Link to comment Share on other sites More sharing options...
Maineah Posted July 9, 2011 Share Posted July 9, 2011 On just about any thing other then a truck the front wheels do most of the stopping. A loaded truck relies on it's rear brakes because there is not much weight shift to the front now if your front brakes are locking there is probably nothing wrong with them and there is some thing wrong with the rears. The rear brakes on your MH have a little gadget that reduces pressure to the rear brakes that is a hold over from the pickup and it is designed to keep the rears from locking and trust me they won't on your MH. Personally I would have a brake shop by pass it. You stated the brakes have not been touched if you are having problem it is possible one or both of the wheel cylinders is stuck it only takes one side of the cylinder even on one side of the MH to really screw it up. It does sound like it's time to overhaul the rear brakes. All brake shoes are organic now and should not cause any problems. Quote Link to comment Share on other sites More sharing options...
waiter Posted July 9, 2011 Share Posted July 9, 2011 Two things come to mind, 1) verify that the rear brakes are adjusted all the way to the drum. Jack up the rear and adjust the shoes until they just start to drag when the wheel is turned forward. (turn the wheel backwards and forwards to unseat the shoes, then adjust the shoes until they drag just a tiny bit when the wheel is rotated forward. repeat the backwards and forward rotation as you adjust. (I think this is probably where your problem is, rear shoes not adjusted) 2) Verify the proportion valve is functioning. I've heard of people disconnecting the linkage and tying the valve open with coat hanger, or simply removing the valve. The valve is on the frame and the linkage attaches to the rear axle. as weight compresses the rear axle, the linkage changes the valve position and applies more pressure to the rear brakes. Since our Toyhouses are equivalent to an overloaded pickup, the logic is, simply put the valve in the max position all the time. John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
bigtiki Posted October 10, 2011 Share Posted October 10, 2011 I just bought a 1985 Sunrader. Previous owner replaced the pads. I am having the same issue....The front left is locking up. On closer inspection, the boob did not replace the bushings that the caliper floats on. They were removed, and the caliper is "floating" on what is left of the rubber inside the caliper housing. I read an article (wiki) that states the single caliper brake will grab if the pins, or in our case, bolts, are bent, or the bushings are not lubricated. I expected mine to be dry...but they were missing. Having trouble finding replacement parts...may have to buy whole caliper asembly. Quote Link to comment Share on other sites More sharing options...
Oldiesel Posted October 11, 2011 Share Posted October 11, 2011 I recently installed air lifts on the rear of or 21ft and after that the brakes were poor and did not stop well at all.Trying to figure out why it finally dawned on me that i had raised the rear back to the unloaded height.I have the factory manual so i adjusted the rear brake compensator linkage all the way ,up which increases the rear brake pressure,this brought the brake function back to normal,so keep this in mind as you add air boosters or overload springs. Don Quote Link to comment Share on other sites More sharing options...
5Toyota Posted October 11, 2011 Share Posted October 11, 2011 This happend to us on a 1986 but it was a four wheel drive the shop put the wrong wheel bearings in the front the brakes would go to the flor going forward and were better backing up the to o big berings were allowing the disc on both sides to flot andmove side to side took a while to find it Quote Link to comment Share on other sites More sharing options...
bigtiki Posted October 27, 2011 Share Posted October 27, 2011 Two things come to mind, 1) verify that the rear brakes are adjusted all the way to the drum. Jack up the rear and adjust the shoes until they just start to drag when the wheel is turned forward. (turn the wheel backwards and forwards to unseat the shoes, then adjust the shoes until they drag just a tiny bit when the wheel is rotated forward. repeat the backwards and forward rotation as you adjust. (I think this is probably where your problem is, rear shoes not adjusted) 2) Verify the proportion valve is functioning. I've heard of people disconnecting the linkage and tying the valve open with coat hanger, or simply removing the valve. The valve is on the frame and the linkage attaches to the rear axle. as weight compresses the rear axle, the linkage changes the valve position and applies more pressure to the rear brakes. Since our Toyhouses are equivalent to an overloaded pickup, the logic is, simply put the valve in the max position all the time. John Mc 88 Dolphin 4 Auto I just was talking to a MH mechanic, and he says that the flexible line leading to the valve in your second photo is suspect if the bleeding pressure is low, or the brakes are not working properly. He says the ones on Chevys are even worse than Toyotas, and he has seen many that are constricted and collapsed on the inside, but look fine on the outside. How can you tell that valve is in the UP position???. I take it the valve is in the second picture. Quote Link to comment Share on other sites More sharing options...
mrgizmow Posted March 10, 2012 Share Posted March 10, 2012 This seems to be a good thread to add my question as I have an 88 Dolphin. My front pads were down to metal and the rotors badly scored. I replaced both and was pleased at the modest cost and the 'apparent' ease as a do-it-yourself project. The rig has 50,000 miles on it. The front bearings looked great, the grease was abundant and clean. I installed new seals as it was suggested and low cost/simple. What I have noted has been a rhythmic squeek that will go away with brake pressure. To me this suggests the pads are rubbing on the rotors (hard). I know with discs there is always light contact of pad and rotor. I expect as well, the rotor will always be warm as a result of some friction. Upon checking with my hands, the hub feel pretty warm/hot as well. I think the bearing adjustment is likely OK but perhaps the constant rubbing of the pads generates enough heat to migrate to the hub when just driving around town, with brakeing of course. I pulled the right side, the pad rotor contact was notable but without the wheel, I could still turn the rotor by hand. There seemed to be an area that was a bit tighter and 'showed' a more obvious contact mark for some degrees, suggesting that the rotor is very slightly warpped or perhaps wheel bearings are loose (I would be inclined to go with the warp). I greased channels in the torque plate, but used the old "pad support plates". I as well, applied some brake grease to the 'like new' slide bushings. Pads and rotors are new, the rest has 50,000 on motorhome miles on them. The pads seem to move comfortably in the torque plate even with the old supports. As well, the slide bushings seem loose and smooth. I noted that the snug contact between the pads and rotor could be minimized by using a C-clamp to push "IN" the caliper piston. After compression, should I expect the caliper to 'suck-in' a bit or simply cease applying pressure. On another post someone mentioned front brake grabbing and was told the master cylinder was the culpret. Since I installed new (non OEM) pads and rotors my thought was to 'lap' the pads a bit to provider a bit more space and less friction/heat. I know I have went on and on, but this is just the way I am. Any ideas as to what else I may be dealing with and solutions/ideas to the problem (s). Thanks folks............. Gerry Quote Link to comment Share on other sites More sharing options...
5Toyota Posted March 10, 2012 Share Posted March 10, 2012 aslong as you can turn them by hand should be ok i would them wear in a bit see how they are disc aways have some contact all the time. if you cant turn them by hand then you may have a stuck claiper. does not happen often happened to me on a toyota wagen somtime ago. my 1988 4wd xtra cab squecks like you describe. the brakes are fine somtimes stops when you hit it lite. done that all years i have had it. bought a 1987 dolphin 60000 miles in nov our 7th toyota over the last 35 years togeter Quote Link to comment Share on other sites More sharing options...
mrgizmow Posted March 10, 2012 Share Posted March 10, 2012 Much thanks 5Toyotas i'm feeling better already. Gerry Found the real culprit: this will be hard to explain unless you have recently had your brakes apart and have the same style I have. On my 88 there are two bent spring wires that fit into holes on the top of the brake pads, they are bent in the shape of a "U". They seem to be responsible for providing a very slight push, forceing the pads away from each other and as a result, they minimize the contact pressure of the pads to the rotor when the brakes are not in use. The give away for me (though this was my second dealing with the front brake) was the difficulty I was having trying to get the caliper bolts lined up with the holes in the torque plate. When doing my brake job I finally got it, but it struck me odd that is was such a chore. What I discovered was that the after market pads did not have holes that were as deep as the originals. The problem that this created was, even though the springs appeared to be properly positioned they stuck up a little as a result of the shallower holes. Though unseen, this conditioned created pressure on the pads because when I clamped the cylinder in place it pushed down on the higher (now contacting) "U" springs. This pressure prevented the springs from doing anything except binding the pads in the grooves they were suppose to float in. I snipped the dog-leg section of the springs so they sat lower. Now the caliper bolts in place very easy and the pads 'float' on the rails more readily. Since it is not all buttoned up and torqued down, I will take it apart again and take pictures. Note contact point at red arrow. This was seen on all four corners of both right and left brake calipers. I know it does not look like much but it was enough to prevent 'floating' of the pads. Brakes stopped fine, but would drag. Test drive is day & nite. Smooth and ho more heat felt on hub. Gerry before: after trimming spring: Quote Link to comment Share on other sites More sharing options...
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