reverendzed Posted August 31, 2008 Posted August 31, 2008 Yesterday had an interesting driving experience! as I attempted to stop at traffic lights what I normally call brakes instantly turned to 'sponge' and almost didn't stop me! from that point if I didn't pump the brakes, the pedal went almost immediatly to the floor, I also saw the 'brake' light on the dash come on for the very first time! everything looked right with fluid, and no fluid that I could see at the wheels (leaking) could this be booster, or vacuum or ? REV> Quote
Woza01 Posted August 31, 2008 Posted August 31, 2008 Well if there is no loss of fluid from the resevoir, and no leakage at either the master cylinder, or at the wheels, then your problem is an internal bypass. Essentially this means that one of the seals that should be pushing the fluid down the brake lines when you hit the pedal, isnt sealing properly and the fluid is passing around it. Usually this means that the bore of the M/C has corroded and/or the seal has decided that life isnt so great any more ! lol. Anyway, looks like youll probably need a new master, or you may be able to get it repaired, but not many places do that these days ! Let me know how you go ! Quote
Toecutter Posted August 31, 2008 Posted August 31, 2008 Dave , might be a good time to upgrade to a 15/16 or 1" MC!? Sulio Quote
reverendzed Posted August 31, 2008 Author Posted August 31, 2008 I'll do a bit more checking on the MC, Sulio can you give a bit more info on your suggestion and also what makes that brake light on the dash come on, is it pedal travel or some sensor? Rev. Quote
Moderators Zedman240® Posted August 31, 2008 Moderators Posted August 31, 2008 The light on the dash is switched on by excess piston movement at the "dual circuit pressure differential switch" brake line junction; when there is decreased pressure in one circuit over the other eg. front to back. Its mounted just underneath the master cylinder in the engine bay, has the short steel lines directly from the MC. I'd say a wheel cylinder has failed and you haven't seen the brake fluid leak yet....Check the rears first! Quote
reverendzed Posted August 31, 2008 Author Posted August 31, 2008 Thanks Dimitri...I'll get under and have a good look tomorrow. I guess like anything this one is going to be a process of elimination. Rev. Quote
Toecutter Posted August 31, 2008 Posted August 31, 2008 looks like Dimitri has given a very comprehensive run down. If you decide to make any brake upgrades I've just installed the commonly done Hilux front calipers. You can pick these up for about $100 and they are a bolt on so if you want to use this as an excuse to upgrade the front brakes the 83 - 89 hilux S12+8 are a cheap and easy upgrade. It made a pretty big diff re not having to push so hard on the pedal. You can also install the 15/16 MC from a 280ZX which I have reay to go and 280zx caliprs Lurch has fitted. There is a US Co that supplies the bracket to bolt on to your exsiting hub and it's about $120 deleivered. Then all you need is 280ZX caliperrs and discs. Here I am enticing you to do all this work when all you need to do is fix a small leak on your existing brakes. Any how Rev, if you want a link to the bracket supplier please advise and I'll dig it up. Cheers, Sulio Quote
Moderators Zedman240® Posted September 1, 2008 Moderators Posted September 1, 2008 If it is a rear wheel cylinder, I was told a while ago 260Z wheel cylinders are no longer made. That's why I did my rear disc conversion about 4 years ago..If you had plans in the future of any brake upgrades, now is the time! Quote
Toecutter Posted September 1, 2008 Posted September 1, 2008 If it is a rear wheel cylinder, I was told a while ago 260Z wheel cylinders are no longer made. That's why I did my rear disc conversion about 4 years ago..If you had plans in the future of any brake upgrades, now is the time! ...ah well you can't et much better rationalisation than that! It's a must now. Here's a bolt on rear caliper bracket that allows you to bolt on the 280zx rear calilpers and discs. Just follow Lurch's Tutorial Artical Thread on the set up. The above are about US$140 delivered from memory, pretty good price I reckon. Link to supplier below: http://store.zraceproducts.com/brakes.php Sulio Quote
reverendzed Posted September 4, 2008 Author Posted September 4, 2008 thanks to all for help and advice with my brake dilemma. turned out i checked all brake cylinders and all O.K so took a punt and replaced the master cylinder, bled all wheels and master and......now I can stop again! and the best part is I did it myself, I think I've learned more in the last 2 years about cars than ever before. Thanks again to the generous donation of ideas, tips and tricks. and special thanks to Mayhem! Quote
Woza01 Posted September 4, 2008 Posted September 4, 2008 Well done dude...always good when you can fix stuff yourself. like I said in my first post to you after you started the thread....you had an internal Bypass in the Master Cylinder. Iv'e seen it a thousand times (I used to work in the Brake Industy ) Keep up the good work dude ! Quote
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