zerow Posted October 4, 2011 Report Share Posted October 4, 2011 I have had the 610 running better and better everyday. But I have come across a problem as of late. I get the brakes warmed up and the fronts start dragging....BAD. smoke coming off of them and everything. The rear seem unaffected, but I know there is a general lag all around. The pedal got progressively harder until it took standing on the pedal to make it stop. The first time I thought it was a fluke, I let the car cool off for 3 hours and the brakes were like normal - like nothing ever happened. Yesterday, I took the car on the freeway and sure as it could be, it did it again. This time I disconnected the booster and inverted the one way valve (just to rule them out) and the brakes still wouldn't retract completely. Here is the build, from front to back: Existing Master Vac booster (holds vacuum), 15/16 ZX brake master cylinder, stock proportioning valve and hardlines (fluid cleared), 280ZX front brakes (all new calipers, hardware, and pads) and Maxima/200SX rear disc brakes (all new calipers, hardware, and pads). Any help would be appreciated. I don't want to end up smashing up this car over not having proper brakes. Thanks! Quote Link to comment
MicroMachinery Posted October 4, 2011 Report Share Posted October 4, 2011 Did you try cracking that bleeder to see if that relieved the pressure? Quote Link to comment
zerow Posted October 4, 2011 Author Report Share Posted October 4, 2011 I need to replicate the condition first. I went out to the car this morning (brakes cold) and they operated as normal. Quote Link to comment
MicroMachinery Posted October 4, 2011 Report Share Posted October 4, 2011 Can you just pump them up in your driveway until they start sticking? Might take a while, but it should do it if it's purely a valving issue. Quote Link to comment
datzenmike Posted October 4, 2011 Report Share Posted October 4, 2011 Can you just pump them up in your driveway until they start sticking? Might take a while, but it should do it if it's purely a valving issue. Your master is not returning back to it's rest position in the bore. Usually the pressure in the lines and the spring ahead of the piston inside the master pushes it back when the peddle is released. Couple of possible thongs: The pushrod on the peddle isn't adjusted properly. There should be about 1/16" of peddle play before the pushrod actually starts to push the piston in the master. Push down on the peddle lightly with your thumb, it shoul move a few mm befor there is firm resistance. The bore is damaged and the piston can't return fully. Water in the master fluid can rust the steel piston and cause it to seize. This is specially true if sitting for a long time. One of the flex lines to the caliper is damaged internally and a flap is blocking the returm of fluid to the master. If both are locked then forget this as i5's very unlikely that this has happened to both of them. If the master does not return fully to it's rest position, not all of the pressure ahead of it can 'vent' back into the reservoir. Each time you use the brakes the pressure builds until the wheel locks. Quote Link to comment
zerow Posted October 5, 2011 Author Report Share Posted October 5, 2011 Mike has hit the nail on the head. Now, to replace this bugger and get back to enjoying the ride in my Datsun. Quote Link to comment
datzenmike Posted October 5, 2011 Report Share Posted October 5, 2011 I swung at three nails, so which one did I hit??? Quote Link to comment
MicroMachinery Posted October 5, 2011 Report Share Posted October 5, 2011 I assume the master cylinder.. it was the only part in his system that wasn't new. If it was a flex line, it would have just been one caliper hanging up. Quote Link to comment
zerow Posted October 5, 2011 Author Report Share Posted October 5, 2011 I'm sorry I didn't specify: I am with Mike on the Master Cylinder. I remember having difficulty in bleeding the system...this would lend back to that day. Also, my inability to get above 45 miles per hour the day of JCCS would lend to this theory (brakes sticking then). I get pedal play when cold. The few mm are there when applied. The fluid more and more looks not as clean as when first put in, another indicator of bad stuff going on in the parts I cannot see. Time for replacement. And time to sell some surplus parts to make some money... Quote Link to comment
zerow Posted October 13, 2011 Author Report Share Posted October 13, 2011 I ended up bleeding the master cylinder , both front and rear, and found a healthy pocket of air trapped in the front circuit. Brakes are now "normal" feeling. I took the car out to the edge of town where the speed limit signs are really suggestions and got the brakes good and hot - no more binding! One thing the sedan couldn't do before when the brakes were hot was "creep" - move forward without the brakes applied or giving any gas. I love how the car feels now, even just a regular cruise speed (35-45 mph) feels like the car is working less to keep it going. Thanks everyone for your help! Quote Link to comment
INDY510 Posted October 13, 2011 Report Share Posted October 13, 2011 . It's funny that all these people believe it actually drives without seeing pics or video .. . .. :lol: Quote Link to comment
zerow Posted October 14, 2011 Author Report Share Posted October 14, 2011 . It's funny that all these people believe it actually drives without seeing pics or video .. . .. :lol: Game On, Indy...<_< Quote Link to comment
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