Introducing the Stig Special

[neil 2,398]

Allmost there now Ian , its getting exciting now . Great video once again especially the little wave at around nine & half mins :laughing-lettersrofl:

[Stigian 1,234]

:D I was waving to my Wife who was waving at me from the house..

[Callen 64]

Very interesting. I wonder if some softer brake pads might help?

[wheeledhorseman 573]

Have sent another email Ian - think Callen is right re needing much softer pads for this type of application but stick with the longer levers as every little will help.

Andy

[meadowfield 2,545]

Have sent another email Ian - think Callen is right re needing much softer pads for this type of application but stick with the longer levers as every little will help.

Andy

long levers, second that - I did suggest to use two deck levers, one on either side.

You only need to look at the levers operating the clutch/brakes on a ZTR mower/Bobcat - Ransomes crawler or even Caterpiller. The amount of torque presented back from a differential is huge when you try stop a wheel that wants to turn. You need long levers to stand a chance of it working. Think of a car too - pedal is over a foot long and travels 4 inches pushing a master cylinder in 1 inch with vacuum assist too ! and even then you can always easily lock the wheels up.

[meadowfield 2,545]

btw, these came in the post - so will be popping in sometime soon !

[JimD 3,345]

I really enjoyed the latest video Ian. The excitement and anticipation builds a little more with each entry. Keep at it and before long we'll see you doing 360's in the yard. We call em donuts over here. Looking forward to your next post. :popcorn:

[AMC RULES 36,945]

The new decals turned out great, can't wait to see them on the beast.

[smoreau 658]

Ok, Your issue with the turning problem has been on my mind. If you look at automotive brakes from a small car to a larger car and truck. Small masters on both, but larger calipers on the larger truck and car. So with that in mind, I would say the duel caliper idea should be better as they will move less and have more pressure behind them. But I don't think that is your problem. If you look at dozers and even the factory drum brake on your 6x6 wheel horse. That small little drum can stop that hole 6x6 because it has gear reduction of the trans to help it. Most Dozers have there brakes gear redacted to aid in there stopping power.

So my thought, or if you could figure out something better, If you could swap out your brake disk with a sprocket and a chain to a smaller sprocket on a jack shaft with your brake disk attached and caliper setup, Your could greatly increase your turning ability with the increased stopping power of reduction. I know that there would be a lot of things to change to do this, but I think it would work.

[Stigian 1,234]

Very interesting. I wonder if some softer brake pads might help?

Howdo Callen, that's a very good thought, I'm not sure if I can find softer pads for Kawasaki gpz305 calipers, I need to do a little research and see if the calipers were used on any other Qwackasaki's.. You never know

Have sent another email Ian - think Callen is right re needing much softer pads for this type of application but stick with the longer levers as every little will help.

Andy

Hey Andy, got the email ta. Yep, longer levers do seem to be helping

Have sent another email Ian - think Callen is right re needing much softer pads for this type of application but stick with the longer levers as every little will help.

Andy

long levers, second that - I did suggest to use two deck levers, one on either side.

You only need to look at the levers operating the clutch/brakes on a ZTR mower/Bobcat - Ransomes crawler or even Caterpiller. The amount of torque presented back from a differential is huge when you try stop a wheel that wants to turn. You need long levers to stand a chance of it working. Think of a car too - pedal is over a foot long and travels 4 inches pushing a master cylinder in 1 inch with vacuum assist too ! and even then you can always easily lock the wheels up.

Howdo Andy, levers are the way to go, the problem I have is finding somewhere to put them. Either side of the hood stand is out as there is only just enough foot space as it is!

More thinking and looking needed me thinks.. It's a shame to think the sliding levers I built might be taken out and chucked in the scrap bin "might come in handy one day" pile..

btw, these came in the post - so will be popping in sometime soon !

Wow!! Thanks Andy, those look fantastic Can't wait to hold them in place and have a look.

I really enjoyed the latest video Ian. The excitement and anticipation builds a little more with each entry. Keep at it and before long we'll see you doing 360's in the yard. We call em donuts over here. Looking forward to your next post.

Hi Jim, it's always cool to get reports on my vid's, happy you liked it. I expect a few 360's (we also call them donuts over here) will be happening, just not in my yard as my landlord would freak if I trashed the lawn. But as luck would have it I'm only one gate away from being in a field

The new decals turned out great, can't wait to see them on the beast.

They do indeed, Mark does some great work.

Ok, Your issue with the turning problem has been on my mind. If you look at automotive brakes from a small car to a larger car and truck. Small masters on both, but larger calipers on the larger truck and car. So with that in mind, I would say the duel caliper idea should be better as they will move less and have more pressure behind them. But I don't think that is your problem. If you look at dozers and even the factory drum brake on your 6x6 wheel horse. That small little drum can stop that hole 6x6 because it has gear reduction of the trans to help it. Most Dozers have there brakes gear redacted to aid in there stopping power.

So my thought, or if you could figure out something better, If you could swap out your brake disk with a sprocket and a chain to a smaller sprocket on a jack shaft with your brake disk attached and caliper setup, Your could greatly increase your turning ability with the increased stopping power of reduction. I know that there would be a lot of things to change to do this, but I think it would work.

Hi Scott, thanks you for devoting part of your brain run time to my steering problem, I'm unable to think about much else at the mo!

I'm cool with what your saying about masters and calipers, it means I've got the right parts... Mostly.

I get what your saying about moving the disc's and a bit of reduction going on, space is the big problem though, there just isn't much space where the disc's and calipers would have to go!

I guess I should grab a spare disc and see what's what tomorrow.

A big thank you to Massey at this point for being a good chap and sending me details of the steering set-up on his tracked horse.

I managed to grab a couple of hours in the shack this afternoon, I bet you can guess which part of the build I have been thinking about

To make life easier one of the cylinders was removed and bolted to a quickly made bracket thingy.. Plenty of holes for adjustment.

Quite what's going on I don't know, despite a huge amount of time spent bleeding every last air bubble out the system I can't get enough pressure up to stop the cylinder from going all the way in until it hit's it's stop!

Brake lever at rest.

Brake lever fully in!

Here's the strange thing...

Although I can't get enough brake pressure up to stop the cylinders bottoming out, I can get enough pressure up to see the calipers trying to bend the disc's!

Er....

I think maybe I should rig up the other sides brakes up the same and take the beast for a "hopefully" spin around the garden/field tomorrow.

[can whlvr 991]

gettin there ian,she will be a one of a kind beast,as someone stated ealier,bobcats dont use brakes,they have a pump on each side,thats why they can spin the tire on each side in different ways,so it it would be hard to compare to your 6x6,maybe two transaxles and a lever for each trans axle ,great progress though and these gremlins are how we learn

[maxed500 10]

just a thought on the steering brakes. Could you open the caliper all the way up and shim the gap between the piston and brake pad? Maybe this would let the master cylinder build a lot of pressure and not bottom out. hopefully I explained this right. Max.

[AMC RULES 36,945]

Keep it up, you're getting closer to completion every day Ian.

I can't wait to see you drinking a coffee, and doin some doughnuts on the beast.

Might should think about installing a cup holder on it at some point...and a seatbelt. :ychain:

[Stigian 1,234]

gettin there ian,she will be a one of a kind beast,as someone stated ealier,bobcats dont use brakes,they have a pump on each side,thats why they can spin the tire on each side in different ways,so it it would be hard to compare to your 6x6,maybe two transaxles and a lever for each trans axle ,great progress though and these gremlins are how we learn

Hi Don, you know I'm going to have to look at the prices of hydraulic motors now you've mentioned them on Bobcat's

Lol at the Gremlins, yep this project is very much a learning process.

just a thought on the steering brakes. Could you open the caliper all the way up and shim the gap between the piston and brake pad? Maybe this would let the master cylinder build a lot of pressure and not bottom out. hopefully I explained this right. Max.

Hi Maxed500, I get what your saying about the shims, the trouble is they would be almost impossible to get in place due the the lack of space around the calipers!!

It's very tight in there!

Keep it up, you're getting closer to completion every day Ian.

I can't wait to see you drinking a coffee, and doin some doughnuts on the beast.

Might should think about installing a cup holder on it at some point...and a seatbelt.

Evening Craig, I might need to grow another arm to drink coffee and drive the beast at the same time!! Saying that an extra arm would come in handy anyway with two steering levers and the motion control lever being used at the same time

Not much to report really, just lot's of brake bleeding, test driving followed by plenty of

The main problem with the steering brakes is I cannot get any real pressure through the system with two calipers each side plumbed in!!

If I lock off one of the calipers then it feels like there is loads of pressure in the system (Although not enough to grip the discs tightly enough!) but if I let both calipers get the fluid flow, then the pressure drops right down and the cylinder bottoms out!!!

I do still wonder if the master cylinders are quite big enough for the job... Bear in mind the the cylinders are for rear bike brakes and the calipers are twins from the front of a Qwackasaki Gpz305.. Not really designed to work together! I did try to research the spec's of the Gpz's front master cylinder to compare the two, but I couldn't find any details on line!!

Anyway, after a few more hours of fiddling with the brakes it was time for another test drive.

Pete's first time driving it up the ramps..

This was the point I thought I really should be somewhere else

Having had enough of the blasted brakes for a while Pete and I turned our brains to sorting out two problems.. Bench height and parking space!!

Now you see it...

Now you don't..

The bench will be going back up, just at a much lower height. One that's a comfortable height to work at. but low enough to make it much easier to get the 6X6 or other projects on and off.

In the meantime my 312-8 was plucked from the garden where it had been hiding under a tarp since "Test drive day", and parked back in the warmth of the shack.

Jumping back to the brakes to finish this update, I guess the way to test if I need bigger master cylinders is to plumb both cylinder to the calipers one side and see what happens! :dunno:

[sorekiwi 761]

Just a wild thought that I thought I should throw out there Ian....

Is there any chance that with all that lever travel, that your levers are going over center? ie the lever travels beyond 90 degrees to the pivot point, so you actually get less force on the master cylinder the further you push the pedal? (hope this makes some sense!)

[Stigian 1,234]

Hi Mike, yep that makes sense

Nope the levers don't travel past 90 degrees.

[Herbl 10]

You might look at a car's master cylinder, as it has a front and rear with a valve for the front calibers, just a thought...

Herb

[Anglo Traction 759]

I'm no expert on Pressure systems, only that I service my own Vehicle Brake systems, but I believe the dilemma may lie in the System Fluid Volume and Actuating Cylinder size.

Add a bit of awkward illusive trapped air and there exists a Pressure problem.

Ian, are the Hoses the same Bore size as say Vehicle Brake Pipe diameter ?. If they are bigger, you could reduce the System volume by using smaller bore pipes or a Bigger Master Cylinder. Would that cause a problem with hand leverage pressure?.

Don't throw any spanners at me, but would it be possible to adapt a Power Steering type pump to the system?. So that it ran off a Pulley rather than Vacuum.

Stick with it, you'll get there.

[Callen 64]

You might try putting some shims between the piston and puck to lessen travel(less fluid movement).

[Stigian 1,234]

You might look at a car's master cylinder, as it has a front and rear with a valve for the front calibers, just a thought...

Herb

Hi Herb, thanks for the suggestion. I have thought about using a car master cylinder, the thing that is stopping me is the pipework. A car uses different pipes and connectors than a bike system so I would have to get some special pipes made.. At a cost! I could cobble something together using both car and bike bit's, but brakes shouldn't been bodged together..

Says a chap who is mixing front and back bike bits together

I'm no expert on Pressure systems, only that I service my own Vehicle Brake systems, but I believe the dilemma may lie in the System Fluid Volume and Actuating Cylinder size.

Add a bit of awkward illusive trapped air and there exists a Pressure problem.

Ian, are the Hoses the same Bore size as say Vehicle Brake Pipe diameter ?. If they are bigger, you could reduce the System volume by using smaller bore pipes or a Bigger Master Cylinder. Would that cause a problem with hand leverage pressure?.

Don't throw any spanners at me, but would it be possible to adapt a Power Steering type pump to the system?. So that it ran off a Pulley rather than Vacuum.

Stick with it, you'll get there.

Howdo Richard, I think you have hit the nail on the head (much better than hitting your finger) there with the "system fluid volume" bit.

After today's "sort the brakes" session I'm getting the feeling that the master cylinders simply don't have the capacity (or push) for getting enough pressure up to push the pistons in two calipers..

Don't worry about flying spanners.. I'd only end up throwing the ones I'm using at the time, and would have to search to find them again!!

But I'm sure I have some empty coffee mate tins I can chuck at you

You might try putting some shims between the piston and puck to lessen travel(less fluid movement).

Hey Callen. I did try something very similar to what you suggest today. Rather than shim between the pads and pistons, I took the calipers away from the discs, pushed the piston fully in, and placed some nice thick spanners between the pads.. With two calipers plumbed in, despite a huge amount of bleeding I still could not stop the master cylinders from bottoming out!!

So what have I been up to in the Shack today? Well most of it was spent bringing my Raider 10 out of hibernation (I can't remember if I've used it this year) to be put on grass cutting duties..

With a sharpened blades it cuts very well

Of course While in the shack I could not resist having a fiddle with the brakes.

Out of interest I thought I would play with the plumbing one side..Still two calipers but each one with their own master cylinder..

20 min's later after making sure every last bubble of air was out of the systems, I had two master cylinders that no longer bottomed out!!

I need to do another little test drive tomorrow with changed tire pressures, but things are looking good

To me, the fact that no matter what I tried I could not stop the cylinders bottoming out with 2 calipers attached, but could with only the 1 caliper, tells me that the cylinders are not big enough to flow the fluid to 2 calipers!!

So... I've just been on Fleabay and bought a couple of Honda Fireblade rear master cylinders with a whopping 5/8" bore. Hopefully they should be up to the job

[COMMANDO6 20]

I was so happy when I saw that the most recent post on this thread was by stigian!

I hope you et the brakes sorted out. fleabay to the rescue!

[Kelly 1,028]

As has been said already, the amount of fluid in the master is used up filling the calipers, before you build enough pressure, I've used check valves/residual valves to keep car brakes from pulling pistons in the calipers back all the way, they hold a very little bit of pressure on the lines to the calipers, that way there is very little filling before the piston starts moving, it helps a lot on pedal travel at least where I used them.

[Stigian 1,234]

I was so happy when I saw that the most recent post on this thread was by stigian!

I hope you et the brakes sorted out. fleabay to the rescue!

This should make you even happier, yet another small update.. Almost daily updates at the mo

Fingers crossed the Fleabay goodies will turn up tomorrow or Saturday.

It's been another day of not much action on the project, the main reason being as Pete and I lowered (very low, it's ground level) the big bench the other day I'm down to only one working bench.. Which was in such a mess that the only way to tell there was a bench there at all was the fact that all the mess had not hit the ground!

Anyway I got the bench clear today and found homes for all of the stuff that had been living under the now very low bench!

Of course the "side effect" of having a tidy up was it gave me plenty of time to thinking about the brakes problem.

My mind kept going back to Massey's fantastic tracked Wheel Horse, or to be a tad more accurate, the steering levers..

Hope you don't mind Massey, I borrowed one of your photo's for illustration purposes.

If you look at how Massey has rigged up the steering lever you can see that the rod that connects to the master cylinder is below the levers pivot point..

That got me thinking..

As my test setup has been..

5 min's of spannering later.. Hhmm, interesting.

Some extra holes drilled later and things are the right way up

Once I remembered that the fluid reservoir should really be above the master cylinder, and after a good bleeding session the brake lever had much more "feel" to it, and try as I might, I could not get the cylinder to bottom out

The question now is, will the new bigger master cylinders have enough oomph behind them to pump up two calipers the same way I managed to get one today?

We shall see :D

[Stigian 1,234]

As has been said already, the amount of fluid in the master is used up filling the calipers, before you build enough pressure, I've used check valves/residual valves to keep car brakes from pulling pistons in the calipers back all the way, they hold a very little bit of pressure on the lines to the calipers, that way there is very little filling before the piston starts moving, it helps a lot on pedal travel at least where I used them.

Hey Kelly, if I've read right, I've done the right thing buying bigger master cylinders. The extra capacity will hopefully be enough to not only fill the calipers but to build enough pressure as well?

[massey 111]

"Hope you don't mind Massey, I borrowed one of your photo's for illustration purposes."

Au contraire, I am honored Sir.