toy_boy Posted January 25, 2010 Report Share Posted January 25, 2010 ok, i'll start from the start: i bought a 130000km 1 owner (old dude lost his license) 5spd ke 70 wagon off the side of the road a couple of months ago. it had been sitting in a padock for about 8 months storing hay. the plan is to get it re-regod for my brothers first car. took it for a test drive, all good but the brakes were pretty (very) weak, best i could describe it is like the car was wheezing to a stop, no bite whatsoever. they did improve a bit after a few hard stops so i put it down to the surface rust on the discs, circa 1983 brake pads and possible air or water in the lines. i bought the car for $275 and drove it home. note, rear drums seem to be working fine, pedal feel was normal (ie it felt like it was getting vacuum "boost") and vacuum lines appear to be fine. i can supply photos if it helps diagnose. just got around to replacing the pads and have run into a bit of a problem. when i jacked up the front end and spun the rotors i noticed the pads were dragging on both sides. took the pads out and they were rooted, only a couple of mm left and gouges out of the pad material. went to put the new ones in but couldnt push the caliper piston in far enough to fit both pads and the rotor. the piston was too stiff for a cheap pad seperator to open fully so i ended up using a G clamp and a fair bit of (slow) pressure. put the new pads in and bolted up the calipers. initially the rotos spun freely but when i pressed the brake pedal the caliper closed but didnt open up again, making it almost impossible to turn the rotor (much worse than with the old pads). i then bled some brake fluid, which released enough pressure that the rotors will turn easily enough but the pads are still contacting. when bleeding it did look like there was some foreign particles coming out in the fluid and maybe a couple of small air bubbles but not much. anyone got an idea of what is causing this and a course of action to fix it? looking to keep things budget but will obviously spend the money to get it fixed. TSRM suggests it could be: 1. clogged master cylinder ports -> check and clean master cylinder and resvior. or 2. frozen wheel cylinder or caliper pistons -> check, free up or renew pistons. at first i thought the master cylinder port controlling the front brakes might not be functioning properly but if that was the case wouldnt the calipers opened all the way when i released the brake fluid? what are the chances that both caliper pistons are stiff and just need lubricating? could i do this without taking the whole caliper apart and overhauling? other ideas? so, what should i do? replace master cylinder? rebuild or replace calipers? something else? if you need more info just let me know any help would be greatly appreciated cheers I'm starting to wish i had kept my rusty old '55 for parts (instead of selling it to someone on here for the same purpose) Quote Link to comment Share on other sites More sharing options...
toy_boy Posted January 25, 2010 Author Report Share Posted January 25, 2010 btw, it has the single piston girlock calipers, don't know if any other types were released in aus. Quote Link to comment Share on other sites More sharing options...
drc_ke20 Posted January 25, 2010 Report Share Posted January 25, 2010 (edited) 1.bleed nipples is partly blocked,replace if needed 2.calipers would suit a rebuild as you mentioned to the top. 3.master cylinder seals are worn out. 4.again master cylinder ports could be rusted and blocked. 5.brake fluid needs to be flushed out as its a build up of moisture in the system 6.check rear wheel cylinders for leaks and check boots and shoe lining. PBR still sells the caliper kits for this.hope this helps? Edited January 25, 2010 by drc_ke20 Quote Link to comment Share on other sites More sharing options...
LittleRedSpirit Posted January 25, 2010 Report Share Posted January 25, 2010 btw, it has the single piston girlock calipers, don't know if any other types were released in aus. Disc brakes always drag, you should still be able to turn the rotors by the wheel studs, however. They don't drag firmly or anything. If its an old car from a paddock, you should probably find someone whos pulled out struts to swap for the arger size and use some that are known to be working. You could go nuts fixing the brakes, rebuild the calipers, spen 120bucks on a new master cylinder, flush then bleed the lines with good fluid, and still possibly not get a great result, while spending hundreds. Ive got a set of struts you can have if you want, just removed and the brakes are good. Then id suggest a better master cylinder, not necessarily new but known to be working. Quote Link to comment Share on other sites More sharing options...
philthy30 Posted January 25, 2010 Report Share Posted January 25, 2010 Hey, sounds like you need to fully overhaul you're callipers and replace the brake hoses while you're there as they can de-laminate on the inside causing blockages. Aslong as the master cylinder operates fine and is not leaking down the front or into the brake booster it should be alright but i would still recommend buying a new one. You can check to see if the boosters working by pumping the pedal without the engine running to remove any vacuum and then hold your foot firmly on the pedal and start the engine. If working correctly the pedal should creep a couple of mm to the floor but it should not continue to sink. Machining the front rotors and rear drums might not be a bad idea either aslong as they still have a bit of meat left on them. The rear wheel cylinders are cheap as chips so id personally just replace them and new shoes if required. Quote Link to comment Share on other sites More sharing options...
toy_boy Posted January 25, 2010 Author Report Share Posted January 25, 2010 thanks heaps guys, this is all good stuff. have to say, I'm leaning towards full rebuild of braking system (new master cylinder, rebuild calipers, new lines, machine discs). rear brakes appear to be all in order, plenty of meat on the shoes etc so i will try not to play around with that end until i have everything else sorted. good to know caliper kits are still available, i was wondering about that. i didnt spend a great deal on the car and the body and interior (sweeet honeycomb patern) are good so i don't mind spending a bit to get it all fixed. looks like it has a BHG or (lets hope not) a cracked head too... DAMMIT... turning into more of a project than i anticipated. cracked head/BHG thread coming soon... pretty sure the booster is working, did the test described when i was first looking into the brake issues and it did exactly what you said. littleredspirit, is that the full strut w/ insert? oem? if not what brand? how much $ you looking for? postage to sydney might not be pleasant, theyre pretty heavy. PM me if you want what do you suggest for plugging brake lines when stuff is removed? i was thinking those little red plugs you used to get with spud guns but don't know if theyre still available. blu tac ok? cheers Quote Link to comment Share on other sites More sharing options...
philthy30 Posted January 25, 2010 Report Share Posted January 25, 2010 what do you suggest for plugging brake lines when stuff is removed? i was thinking those little red plugs you used to get with spud guns but don't know if theyre still available. blu tac ok? cheers Best thing is to drain all the fluid and just wrap a rag and sum tape around the end but you can get the brake hose clamps to put on the hoses or vice grips and a rag (rough) But i wouldnt be to worried about it if youre going to replace the hoses and flush the lines out eventually. Quote Link to comment Share on other sites More sharing options...
towe001 Posted January 26, 2010 Report Share Posted January 26, 2010 btw, it has the single piston girlock calipers, don't know if any other types were released in aus. Ke55 used them as well. Just would have to check cause i think they also used Sumito (or some spelling) on the earlier models. But on that note also ke3x. The brake rotors are the same as well. So are the wheel bearings.... Quote Link to comment Share on other sites More sharing options...
toy_boy Posted January 27, 2010 Author Report Share Posted January 27, 2010 Ke55 used them as well. Just would have to check cause i think they also used Sumito (or some spelling) on the earlier models. But on that note also ke3x. The brake rotors are the same as well. So are the wheel bearings.... i'm painfully aware of these similarities, sold a ke55 with perfect brakes for parts not 6 weeks before i worked out how bad the ke70's were. didnt realise they went as far back as ke3x though. at this stage the plan is something along the lines of: 1. flush all lines front and rear until new brake fluid is coming through. this should make sure I'm not putting dirt into new/rebuilt components through old fluid. test. 2. take apart calipers, if they look serviceable i'll rebuild, if not i'll replace with some known to work. replace front brake lines and bleeder niples. probably get the discs machined. i'll price machining vs new discs and rubber vs braided lines. test 3. if things still aren't right i'll replace the master cylinder. might consider rebuilding if it looks ok and kits are available. test 4. next look at the F/R bias valve a bit more closely. can't really see where the problem could be here, other than blockage. test 5. if theyre still not working... GRRRR! ... ? are the front and rear brakes on seperate enough circuits that messing with front lines/calipers wont require re-bleed of the rears? not a big deal either way, just wondering. thoughts on rebuilding vs replacing? rebuilding is cheap, would maintain 100% originality on the car. i also like how this type or rebuildability is so far removed from todays disposable society. replacing is more expensive (not really a huge factor) but easy and "guarantees" that the part will work as required. i would only go down the rebuild route if could identify exactly what was wrong eg broken spring and the "main component" was A1. going to check prices/availability and take it from there cheers Alex Quote Link to comment Share on other sites More sharing options...
LittleRedSpirit Posted January 27, 2010 Report Share Posted January 27, 2010 i'm painfully aware of these similarities, sold a ke55 with perfect brakes for parts not 6 weeks before i worked out how bad the ke70's were. didnt realise they went as far back as ke3x though. at this stage the plan is something along the lines of: 1. flush all lines front and rear until new brake fluid is coming through. this should make sure I'm not putting dirt into new/rebuilt components through old fluid. test. 2. take apart calipers, if they look serviceable i'll rebuild, if not i'll replace with some known to work. replace front brake lines and bleeder niples. probably get the discs machined. i'll price machining vs new discs and rubber vs braided lines. test 3. if things still aren't right i'll replace the master cylinder. might consider rebuilding if it looks ok and kits are available. test 4. next look at the F/R bias valve a bit more closely. can't really see where the problem could be here, other than blockage. test 5. if theyre still not working... GRRRR! ... ? are the front and rear brakes on seperate enough circuits that messing with front lines/calipers wont require re-bleed of the rears? not a big deal either way, just wondering. thoughts on rebuilding vs replacing? rebuilding is cheap, would maintain 100% originality on the car. i also like how this type or rebuildability is so far removed from todays disposable society. replacing is more expensive (not really a huge factor) but easy and "guarantees" that the part will work as required. i would only go down the rebuild route if could identify exactly what was wrong eg broken spring and the "main component" was A1. going to check prices/availability and take it from there cheers Alex If performance is more your thing than originality, you could swap struts to ae86 ones. You get a bigger brake and strut insert size, so you can buy some konis or bilsteins etc. Its easy to do you just use your ke70 strut tops. Quote Link to comment Share on other sites More sharing options...
seabiscuit Posted January 27, 2010 Report Share Posted January 27, 2010 Getting everything rebuilt that isn't fully working is a lot more tedious and probably expensive than getting replacement parts. If you run down to a pick-a-part wrecker, you'll be able to score a whole set of struts for cheap. Could even try and get some AE86 items! If not, you could buy a whole KE70 strut, master cylinder etc. and keep it all "original" as all the parts are the same and it would be a lot cheaper than to take apart, hand in to a service shop, get them to machine it all down, clean out, rebuild etc. Plenty of people wrecking KE70's here too. Quote Link to comment Share on other sites More sharing options...
toy_boy Posted January 27, 2010 Author Report Share Posted January 27, 2010 If performance is more your thing than originality, you could swap struts to ae86 ones. You get a bigger brake and strut insert size, so you can buy some konis or bilsteins etc. Its easy to do you just use your ke70 strut tops. I have a MA61 supra for performance... well compared to the rolla anyway. the ke70 is all about cheap reliability and me not spending too much time/$ on it. brakes + head gasket fixed = Rego + Drive (in theory) if in the future it was to get the 4ag or 2rz treatment id definitely be looking at bigger brakes but for the moment its not essential. i will keep an eye out though, if some '86 struts come up for the right price its hard to say no to better brakes and bigger dampers. i do agree about the tedious-ness. only really likely to be the calipers and thats just a few seals and a bit of cleaning, couldnt see a rebuild kit being too exxy. if the master cylinder is the culprit ill probably just replace it. theres no urgency to finishing this, my main motivation at the moment is lazyness. I want garage space for the supra, i can put the wheels back on the rolla to move it out easy enough but if i fix the brakes first thats one less time i have to jack it up and take the wheels off. its a fine line between lazy and efficient. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted January 27, 2010 Report Share Posted January 27, 2010 Stick to Plan A- Strip and clean the calipers and you may find the whole problem vanishes. The brake fluid gathers dust as it seeps past the seals over the years and if the car sits for a year it will harden up and stop the pads going back in. Just push the pistons right out and clean pistons & cylinders, drain the fluid out while you clean and lubricate the swinging caliper frame then put it back together. If it works nicely then worry about replacing seals... If you find the caliper cylinders pitted and rusted then worry about replacement options- Quote Link to comment Share on other sites More sharing options...
cableties Posted February 2, 2010 Report Share Posted February 2, 2010 hey I'm agreeing with the above, sounds like the problem is mostlikely with in the caliper its self ie, pot being rusted in the bore... if this is the case then bin for the calipers is the better option. but also cheaking that the caliper slides havent rusted up is good too, best thing i reakon is take the calipers apart... inspect condition and then remove all the slides and hit then on the wire wheel... then re grease and put back togeather........JUst FIY if you do take the calipers apart and find theres nothing wrong, i advise getting a seal kit for them anyways, those seals are probaly as old as the car.lol cheers mate Quote Link to comment Share on other sites More sharing options...
Evan G Posted February 2, 2010 Report Share Posted February 2, 2010 use the special prb rubber grease, use compressed air and a rag to push the pistons out (WD40 maybe required) push the piston out on a rag on the table, so it doesnt go flying and damge it Quote Link to comment Share on other sites More sharing options...
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