ZUKIWORLD Online | Suzuki 4x4 Editorial and Forum
ZUKIWORLD Discussion Forum => Suzuki 4x4 Forum => Topic started by: Rhinoman on October 21, 2005, 03:32:52 PM
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I finally got a day off work today ;D Thought I'd make a start on swapping the LWB brakes onto my Vit.
Pic showing how much thicker ventilated disc is. I contemplated spending some time cleaning up the disc but then decided against it as it will only go rusy again first time it rains:
(http://www.rhinoman.org/mods/images/brakes1.jpg)
This was a surprise, the top disc is the original 8V SWB with Lucas/Girling caliper, the lower is the LWB disc, notice that the SWB disc has a much greater swept area. The other side of the LWb disc was similar to the SWB, both discs were the same
(http://www.rhinoman.org/mods/images/brakes2.jpg)
Ventilated disc in place. I had to spend some time cleaning up the rear mating face with a wire brush to get the disc to sit square. When I first checked the runout I thought it was warped! The disc shield/guard rubbed a little as Wild said it would. I considered modifying it but I have had problems with trapped stones (what a noise!) in the past so I just cut it off.
(http://www.rhinoman.org/mods/images/brakes3.jpg)
LWB piston next to SWB caliper, not easy to see the difference like this
(http://www.rhinoman.org/mods/images/brakes4.jpg)
Vernier calipers show a difference of around 4mm, LWB is 53.5mm against 48.1mm for the SWB.
(http://www.rhinoman.org/mods/images/brakes5.jpg)
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Caliper bolts straight onto SWB hub, the paint I used wasn't completely hard and some of it got smeared when I fitted the caliper. I'm not too fussed, the main reason for painting the caliper was to keep everything clean when I reassembled it. The paint is some high temperature radiator paint from the local DIY superstore, choice of colours was very limited, I couldn't fine any 'proper' brake caliper paint locally.
(http://www.rhinoman.org/mods/images/brakes6.jpg)
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looking good.
does this mean we are going to see the vit back out and about then.
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Not for a while still lots to sort. At least I have somewhere to sort stuff now I have been doing the brakes in between rain showers. While it was raining I hooked up the lights in the garage and installed the first power point too. Now I have a watertight roof, a bench, lights and power - luxury, pity the Vit won't fit in it, lol.
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didn't make the shed big enough then, did we. ;D
At least you have a garage.
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I replaced the other side today. Now I have to make sure that the m/c can push enough fluid to operate the bigger calipers and the rear disc conversion. There isn't enough room for a bigger booster
(http://www.rhinoman.org/mods/images/brakes7.jpg)
So its time to hunt for a bigger master cylinder. I pulled the stock one to strip it and measure it up. There is a plastic cover over the end of the piston. Its not shown in the FSM and doesn't look like it will come off without damaging it in some way. The end of the piston is 5/8", the outer diameter of the m/c is 1" so the piston is more than likely 7/8.
(http://www.rhinoman.org/mods/images/brakes8.jpg)
I won't be able to visit any breakers until next w/e. Heather (IIRC) posted the size of a Subaru m/c as 1 1/16" so I am optimistic that I will find something to suit, I might have to hunt around a bit though.
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My stock mc works fine with the bigger brakes on the toyota axles.
you sure you need to change it????
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I don't know about the Toy axles on the LWB, I would imagine that the bigger brakes would need less pressure to achieve the same braking effect so up to a point maybe it cancels out. With the rear discs there is far too much pedal travel, the rear calipers are free and the handbrake adjusts up properly so I know they're not faulty. Nick fitted a Residual Pressure Valve to his to reduce the problem. The Residual Pressure Valve was designed as an anti-syphon valve for cars with the m/c below the level of the rear brakes, I'm sure it works but the problem is not enough fluid and I would rather fix it by sorting that out. I still wonder if the LWB is different in some way, its possible that it could have the same bore m/c but a different pedal box/mounting arrangement that would give it a longer stroke. To achieve that on a SWB would mean moving the pivot point, which is possible but would put the linkage at a poor operating angle (IMO). Even that may not be possible as I haven't looked at how much of the possible stroke is actually used.
1 1/16" will push a 47% greater volume, 1" will push 31% more. I will have to see what I can find.
I have been looking at a few threads on other boards it definately seems like the Subaru m/c is the way to go with rear discs. I have also discovered that there is a Subaru breaker in High Wycombe too ;D. Fingers crossed that the Lucas m/c is a straight copy of the Aisin version.
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fingers crossed, fingers crossed. ;D
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I have been runnning the bigger brakes on my swb for a year plus now and the improvement in braking was noticable. they made a big difference even on the stock M/C.
its been MOTTED as well with no issues on the brakes.
I think sometimes you knwo to much which gets you thinking ???
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I have been runnning the bigger brakes on my swb for a year plus now and the improvement in braking was noticable. they made a big difference even on the stock M/C.
its been MOTTED as well with no issues on the brakes.
I think sometimes you knwo to much which gets you thinking ???
Yes but you don't have the discs on the rear. Its that that is the real problem not the fronts, I haven't at any point said that you have to have a bigger m/c because of the LWB fronts. Mine was MOTd as well but the brakes were still rubbish.
Theres more info on the swap here:
http://bbs.off-road.com/ubbthreads/showflat.php/Cat/0/Number/1205468/page/0/fpart/1/vc/1
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I'm pretty busy with diy stuff this weekend although I did manage to get to a local breakers today. I had to go to the local tip and there is one right next to it :). I found out that my master cylinder is exactly the same fitting as some Rovers, which is good because parts for them are cheap. The couple I saw were two port and the Vit is three port. I will phone a Rover specialist in the week and try and find out if they ever made a three port.
While I was there I grabbed a 2 port m/c from a Rover 416, it looks slightly bigger in diameter (maybe 15/16") but most importantly it is disc/disc. If there aren't any 3 ports then I will use that with a splitter.
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good to see you back and fiddling around again - we must get that Wiltshire trip done when the Vit's back off the road
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Yeah, that would be good. I liked laning in Wiltshire, have to see what the government have left us now though.
I'm going to try and get round to stripping both m/cs in the week just to see how different the rear brake piston set up is and also so I can get an exact measurement of the pistons. I'm guessing the Rover one is slightly bigger because the body is a couple of mm bigger.
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I'm gonna fit Swift rear disc callipers because they have a handbrake fitted in them. I've looked at the swift MC and the dia is a little smaller, but the swift front callipers have a bigger cilinder. So I'm gonna try to fit the swift rear callipers and MC. If I'm thinking about this right, the swift MC should push enough fluid to the front callipers (as they're smaller) and also to the rear, because they are what originally is fitted to the MC. Am I overlooking something here? Or might this be something to try for you too James?
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I'm gonna fit Swift rear disc callipers because they have a handbrake fitted in them. I've looked at the swift MC and the dia is a little smaller, but the swift front callipers have a bigger cilinder. So I'm gonna try to fit the swift rear callipers and MC. If I'm thinking about this right, the swift MC should push enough fluid to the front callipers (as they're smaller) and also to the rear, because they are what originally is fitted to the MC. Am I overlooking something here? Or might this be something to try for you too James?
That should work OK as its a disc/disc unit, I'm a little surprised that the Swift m/c is smaller. Does it have a size marked on it? it may be just a different thickness body. The real problem with the disc drum master cylinder is that it doesn't push enough fluid to the rear calipers. That means not enough pressure and as a result the front brakes are poor too.
Theres a couple of reasons why I didn't try the Swift m/c. I think the Swifts were all Japanese built so they would have Jap brakes, the fittings are a bit different from my Lucas brakes. The local breakers isn't very big and the only Swift there was disc/drum. Rovers are a straight swap and are plentiful everywhere in the UK. They also depreciate really badly so the parts are very cheap ;D
I'm still looking for a slightly bigger than stock m/c (mine is 7/8) to go with the lwb calipers. Reading Mark and Tony's comments I am less bothered about it now but I would like to maintain the front m/c to caliper diameter ratio , a 1" should be ideal.
Have a look under the Swift and see if it has a combination valve, you might need that too. If you have too much rear bias then try some lwb brakes. Let us know how you get on.
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Lol I forgot to mention only Swift GTI's had rear discs ;) but the Vit MC is 22.2 mm or 20.6 and the Swift GTI is allways 20.6. It should be logical that the Swift MC pushes more fluid to the rear, but I'll try and find out (will take me some time though.... maybe another christmas project ;)). My Vit is Canadian build so I have to find out about that fitment too, but at least it aint spanish ;D We don't have as much rovers over here but if this don't work I'll dive into that direction too I think. Don't know about the combination valve but I'll ask around to find out ;)
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Could the lack of pressure be the LSPV ???
I thought the pistons were the same size for
the front and rear brakes, ,unless there is some
sort of stepped piston in the M/C I don't see
how there could be with a single piston M/C
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Could the lack of pressure be the LSPV ???
I thought the pistons were the same size for
the front and rear brakes, ,unless there is some
sort of stepped piston in the M/C I don't see
how there could be with a single piston M/C
The outside diameter is the same but the piston for the rear brakes has a rod in the centre of it to operate the front brakes in event of a rear brake failure. That means that its effective surface area is much smaller so it displaces less fluid. From what I've read the disc/disc m/c is a slightly different design. I intend to pull them apart to verify that as I haven't been able to find a drawing for a disc/disc m/c. I came across this yesterday while looking which is pretty clear on the subject.
DISC / DISCÂÂ
A four wheel disc brake master cylinder is designed to supply more fluid pressure and volume to the rear disc brakes than the disc / drum master does. This is acheived through an internal piston re design. The piston that feeds the rear brakes on a disc / drum master will run out of stroke, limiting the amount of fluid pressure and volume that may be supplied to the rear isc brakes.
The four wheel disc master re design delivers the extra needed volume and pressure to the rear allowing your rear disc brakes to function properly. If you attempt to use a disc/drum master on a four wheel disc system you will get poor rear brake function and experience a spongy brake pedal with a long pedal travel.ÂÂ
That was taken from here:
http://www.mpbrakes.com/masters.htm
What that doesn't mention is that the front brakes are operated by the pressure in the rear brake circuit. So bad back brakes = bad front brakes too.
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Question on the vented rotor swap.ÂÂ
Do you only need the new rotors, pads and calipers from a 4-door? Does the LWB caliper just bolt up to the same caliper bracket as the SWB one? If so, and the master cylinder will supply enough fluid for this upgrade (not doing rear discs yet) I just might give it a shot.ÂÂ
I always like to have better brakes.
Mike
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Yes, but make sure you get the caliper mounts too,
those are different from non vented units
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I just fitted the complete caliper assembly straight onto the SWB hub. I think thats what Wild means ??? you need both halves of the caliper.
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Yes, that's what I mean
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Bonfire night preperations and darker evenings have meant that haven't progressed very far with this but I managed to find time to strip both m/cs at the w/e. The Rover m/c measured 22.2mm (7/8) and the Vit m/c is 20.6 (13/16) so the sizes tally with the Jap m/cs. I wonder if Nicks has the larger m/c which would explain why his rear discs seem to work a bit better than mine.
As expected the construction of the Suzuki disc/drum m/c (bottom) is quite different from the Rover disc/disc m/c (top). The Suzuki m/c has a small diameter shaft running through the centre and the green valve which looks like the residual pressure valve is secured on the end of the shaft by a circlip. The spring rates seem a litttle different so it looks like the disc/disc m/c gives a longer stroke on the rear at the expense of less stroke on the front, that may be offset by the fact that the Rover cylinder is a bit longer (but the pedal travel would be the limiting factor). In my case the larger diameter of the Rover m/c will offset this, it would be interesting to see the internals of the Swift m/c. The Rover m/c just has two pistons and two springs, the piston for the front chamber has a slot in the middle and a pin runs through it to prevent the piston coming back into the rear chamber.
I have found out that Rover 820s and MGFs have a three port m/c so I am trying to track one of those down, should be a bit bigger too ;D
(http://www.rhinoman.org/mcs.jpg)
The other surprise was how little was holding the Zuk m/c together, you can see in the pic that the Rover m/c has two moulded in clips on the plastic cover and a circlip underneath holding the piston in. The cover on the Zuk is a press fit with no circlip underneath, so it relies on the mounting bolts to hold it together.
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My Rover 820 m/c arrived today. Brand new £35 with cap ;D but its a 2 port, even though they told me it was a 3 port. It is a decent size though so I'm going to run it. I just need to get a splitter and re run the front brake pipes.