Hey there, I'm currently looking for a stuffed old slave cylinder. I don't need good condition so I'm hoping to save a few bucks but will settle for a good one and pay accordingly.
Will be getting it bored out for far cheaper than the 'big release' one from Japan.. Take that FEED! So hoping someone can help me out.
I think there's a slave or two in the pile Anders! Hobbling around at the moment with ligament damage, but trying to get over there tomorrow and will have a squizz.
Not sure how thick on the ground the brake joints are up there, but had a slave and master SS sleeved and kitted last year, it ran $66 for the slave.
Oh sweet, let us know if you find one. Hopefully u get to take it easy with a bit of time off at least!
Local guys up here quoted work WAY too much for an exchange bt50 cylinder a while back so i didn't even ask around locally, I found some guys in SA that are willing to bore it out and I'm looking about $120. I think thats a decent price for a custom job, but then less $$ would be even better. Who are the guys you used? Wondering if they'd be able to do the same?
I'm hoping to get the cylinder out to 7/8 at least from the stock 3/4. 15/16 would be perfect with the OS push conversion I think but probably a bit too extreme..
Did ask some years ago, but even the locally uprated exedy plate here isn't too bad, they said they could bore it out and hone no troubles.....as they do that for the relines anyway. They didn't want to go to the trouble of going through their catalogue to see what might be compatible for the bigger size though, as they're pretty busy and no profit in spending time dicking around there.
Burt Bros is the company, they've been here for decades and they do a lot of the work for the other workshops in the metropolitan area, plus trucking companies and fleets, etc. I'd be amazed if the cost was much different, unless the kit used was only available genuine oem.
Can't find it now of course, but there was something on Rx7 club in the last 12 to 18 months about some guy discovering the Feed slave for the first time and someone in that thread had the details of a vehicle that would match for a bigger homebrew kit. I think the feed size is as about as big as you can go without getting too thin.....porosity might come into play as well worst case. Sort of vaguely remember the title of that thread was weird and not entirely on topic!!
I had a hard time finding any info about bigger slaves, seems to be a rare mod in the rx7 world, gtr guys have the luxury of an off the shelf 15/16 cylinder for only $75 the pricks!
The OS twin plate with the push conversion seems to only need half the stroke of the stock cylinder, with engagement set close to the floor half my pedal is just free play. At the strip the clutch is almost useless on street tyres, bias plys would be the only way to make it work atm but too much money when u need to run them on every corner.
I'm thinking a clutch masters or tilton slow release valve with the bored out cylinder would make a massive difference off the line
Not sure if a 4runner is particularly unique, hilux probably the same? Seems that's 13/16" from the 3/4" standard size. The other way is a smaller master, but doubt there's much below stock 5/8" available anyway and you get a longer pedal.
Those push/pull conversions, haven't really looked closely at the one in the junk here, is there adjustment required in push-rods to get them to work properly?? Half travel sounds nuts, unless there's lots of lost motion in clearance take-ups, I might check if there's something like a pedestal spacer required.
If you have access to a mill, you could do a concentric slave conversion, which is the absolute rolls royce for feel and control. Drew from direct clutch did a retrofit on his thing a few years ago, but expect it cost more than a few bob using "name" components. Here's a bellhousing on one of the things here, using the rest of a rx7 box as a basis, (saab slave) to give you an idea -
Awesome to hear how much improvement there is with the feed cylinder, can't wait to finally make this thing usable! If it was just $260 I might have grabbed it but with rhd that's sure to end up more like 350, been stung too many times there.
Sounds like 13/16 is what the feed cylinder would be and a pretty safe step up. Old mate said 13/16 should be no problem but see how we go getting to 7/8. Worst case I can send my cylinder down, just much rather swap in and out all at once.
Do like the idea of the concentric slave! I only started hearing about these things after doing the OS conversion but no money burning a hole in my pocket unfortunately
Always surprised with the endorsements of rhd, but maybe the service and costs have improved since I last used them....certainly wouldn't be hard to achieve.
After lots of ride height and scaling work today, the sieve on my shoulders, forgot the measurement of the dust boot groove, it's slightly over 1mm deep from memory. You can see otherwise 25mm OD for the cylinder , say ~23mm at the groove, SFA .38mm wall thickness at 7/8" bore, so you can understand Feed going for the smaller size.
Had a look at what I think is an ORC pull/push conversion, about the only lost motion there is between the fork and the thrust bearing. Checking a clutch pedal (very low mileage), and looked at adjustment at the clevis and found a fair bit of slop, plastic bush was flogged out and the hole ovalised - expect most FDs are in the same boat.
I was hoping the dust boot lip wouldn't limit the bore size too much, I figured maybe a bigger boot could be tie wired on but if the cylinder is only 25 mm OD, a 22.2mm 7/8 bore would be a little dodgy and doubt old mate will do it. 13/16 is 15% more surface area and would make for a fair improvement I guess.
In my searching I found a 7/8" Mazda t3500 bus cylinder that had a similar mounting setup, I wonder if there is a way to make it fit.. Might be a project for the future.
Looks like my master cylinder has seen better days too!
That cylinder in your pic looks a bit too good to part with, don't suppose you have another crappy one you'd be willing to sell?
There would possibly be a way to make a bigger one, if you were really keen, but getting into concentric slave territory on the labour side. Turn off the end, make a piece in steel and shrink fit it into the slave, then zip tie/wire the boot on. Shouldn't matter with the seal riding about 15mm beyond the end of the slave. Problem would be holding the work accurately, need something with touch probing to accurately locate the centre for boring - and the sleeve joining the two bits would be need to be very thin where it inserts into the slave.
Wouldn't be surprised most of the mazda stuff is common bolt centres, that bus one looks like it mounts on the other side going by the machined surface, bleeding a bit more difficult too, if it could fit. I think Aisin probably made the hydraulics, as in most Jap cars, but that would be a fun job trying to work out what might work, even if there's a catalogue!
Mazda was definitely having a lend with the plastic bush in the clutch pedal pushrod pivot, does look like you've got a bit of movement with the witness marks. The .5mm wall thickness might have got you out of the dealership and home I reckon before giving up!!
Pedal ratio looked lots more than the brake, probably 6:1 or so, 2mm slop could end up 1/2" at the foot, might pay to drill and bush that eventually.
The slave looks pretty much like all the others, they always fuck up inside no matter how good on the outside and Burts blasts the paint off anyway, definitely owe you one for the speedos too. Touch wood, on the hoist the tacho is behaving itself and not going epileptic, soon find out if it works with lots of coil noise, etc, in real life.
If you think the master is suspect, the stainless re-sleeve for those was $93.50, have lots more of those hanging around, they must be breeding for some reason and wouldn't mind thinning the herd. Anyhow, if you want to go 13/16" I can drop the slave over there this week....I'll double check the groove depth and actually write it down this time.
Well, the bus cylinder was cheap enough I decided to buy one and see how it fits... This should be interesting lol. So might hold off for a moment boring out an oem cylinder, I'll let u know if it's needed. Cheers for the offer!
It looks like I have a fair bit of room to fit it in and the bleeder shouldn't be too awkward. I have some half assed ideas about making it fit The clutch line inlet is the only questionable part I think.
Measured the groove, I suspect it should nominally be 22mm, but this one seemed a touch over - no chance of 7/8" anyhow.
Looking at you clutch pedal again, that switch should be contacting the pad....not sure if that's the thing that stops you starting in gear or something equally useless. Came across another pedal too, which must have come from V8 Steve (Walt K?), absolutely slop free by some stroke of luck.
Ah I see the little bush you mean in your pic now. Will have to check that, probably is long gone on a 93 FD. I think the reason for most of the free play is how much I shortened that master cylinder rod to get engagment closer to the floor where its nice and predictable, this setup really only needs what feels like 2-3 inches of pedal stroke to disengage fully and there's only a few mm where the clutch can be ridden. Not much fun!
Can't wait to see if this new cylinder fits, would really transform the car! I really had no intention of trying to fit a completely different cylinder but the vote of confidence on the bolt pattern possibly being the same made me go for it. Can hopefully modify it to suit otherwise.
Not sure what's up with the brown plastic thing either, thought it didn't look right but can't move anything to make the proper contact. Bothers me a little but I'm not too OCD about that kinda stuff
This is less of a WTB and more of an experiment now but got my 7/8 cylinder today and I'm thinking it's gonna work! Not exactly bolt on fitment but shouldn't take too much modification.
Bolted up to the oem slave cylinder spacer perfectly however the OS giken spacer is a little thinner and the new cylinder has a 10mm longer 'nose' on it. Definitely gonna need to space it out as there is a lip in the bellhousing that stops the cylinder from going further in.
2nd issue is the position of the top bolt that would be inaccessible due to the inlet and bleeder. Plan is to bleed the slave on the ground and bolt it on upside down.
Hoping the new cylinder has the same thread for the clutch line as the FD too.
Excellent! Cylinder was listed as 80's through to late 90's T3500, there is a 3/4 cylinder version also I found that's worth noting if someone attempts this in the future and a lot of the ebay jobs aren't labelled.
Sucks hairy balls working in that area though, a hoist is high on my wish list right now
The 7/8 Mazda cylinder works a treat. Feels like the rolls Royce of twin plates now, light as a feather and super wide engagement point basically like you would expect from any oem setup. Can't compare to the stock FD clutch as I've never used one but I'm certain this feels lighter than the bt50 work ute
I've wound the master cylinder rod right back out to factory free play specs, definitely a bit of slop in that bush mention earlier. But clutch now starts to engage about an inch off the floor with a full pedal of travel. Stoked as!
The thread pitch on the new cylinder was the same as the FD but it didn't have the 'inverted seat'? So no go there. A trip to auto barn and $70 worth of speedflow later I had everything I needed, fittings needed were all pretty common.
I made some studs and used a washer and bolt for spacers as this was the easiest way to get the spacing needed with easy assembly. 9mm of spacer worked perfectly.
Bit late now, if you already had a stock length stainless clutch line rather than the stocker, could have saved some coin with just steel tube nuts, last time I bought them at least, they are about 20 cents each, in both seat varieties. You'd possibly need another bit of 3/16" hardline to make flaring easier though?
Thanks for all the info mate, wouldn't have got to this point without all your knowledge. You must have a hell of a lot of experience!
Hmmm I did have a stock length stainless hose but wasn't sure how to adapt it, haven't really done anything with hardline before. Sounds like it definitely could have been done cheaper. To start from scratch with teflon braid the female inverted fitting was the most expensive at $30. All in all it cost me $120, same cost as boring but with a better result. Postage would have added to that $120 for boring out too. I jewed the shit out of this!
If a mod wants to they could move this thread to tech and rename it something more searchable?
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WTB: Old slave cylinder
The clutch line inlet is the only questionable part I think.
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