Bias box multiple problems

[Iain]

Am I going mad here or does none of this work with eachother?

Problem 1: Reservoir fittings, threads right but they both look like convex to me

http://iainel.co.uk/images/forums/Misc/rps20151223_114554_607.jpg

http://iainel.co.uk/images/forums/Misc/rps20151223_114613_810.jpg

Problem 2: Master cylinder pushrod length. It's too long, if I cut it down it'll be right at the end of the threaded section, is that OK for adjustability? Pic shows it wound all the way in and how much I'd need to remove.

http://iainel.co.uk/images/forums/Misc/rps20151223_114638_359.jpg

Problem 3: For some reason the M10 thread coming out the bottom is a good 7cm+ shorter than the standard one, what am I supposed to do here, bodge it up with threaded sleeve and extra rod until it reaches the pedal?

http://iainel.co.uk/images/forums/Misc/rps20151223_111851_503.jpg

[Peredur]

Personally I'd ring Hockly and ask as after all it's their product and it should be supplied good to go.

[Iain]

Promised a call back on Tuesday but didn't, all they said upfront was they don't use Wilwood master cylinders. The pushrod measurements I can see on the Wilwood site match the AP master cylinder specs though. If I find a replacement over xmas it'll be going back. Just nice to check I'm not being daft and doing stuff wrong!

[Peredur]

If it's any help then problem 1 shouldn't be a problem as I know of a load of lads running reservoirs like that just threaded straight into the cylinder, problem 2 might be a problem dependent on how the balance bar is set and I've no idea on problem 3. I've had no dealings with Hocklys myself but I know that allan at Pro-Tec is very helpful.

[Iain]

Protec were helpful when I talked to them, I was thinking of theirs.

Ive just picked up another second hand bias box and you're right #1 isn't an issue. #2 is exactly the same on this other box, cut down push rods and no thread left. #3 I'm going to have to rig up a connecting bar to suit the pedal I guess.

It's just #2 I'm pondering now. I could space the master cylinders out from the box with washers?

[Peredur]

I suppose you could space them out (make some ally or nylon spacers if you can) so long as there's enough thread on the mounting studs to bet a nyloc on it should be ok

[toymex]

I found I had to space the rear cylinder to get the bias to work properly and have had to cut the bars on nearly every bias box I have fitted ,also had to put washers either side of the bias assembly to get the bars parallel

[Iain]

Good stuff sounds like I'll need to cut them and space them out from the bias assembly slightly in order to get the balance bar horizontal.

Feels bodgy but oh well

[dan23]

Have a look at thread extensions from tool station it's basically a long nut around 50 mm long you can use to extend the rod
( is there a way to direct link photos on here ? )

not sure were I meant to be looking in the pic can you remove the rod an run a tap down it to extend the thread

[boffer8]

I had all these problems, trimmed down the push rods to suit and are now fine, trimmed the M10 threaded section so I could get the pedal position Bob on for where I wanted it to be and the reservoirs are a standard size as most people remote mount them somewhere. Depending which ones you have it will be tough to fit them next to each other due to spacing as it is

[Iain]

Good stuff thanks guys. I'll check those extension rods out on toolstation.

Boffer my main concern was I'd run out of threads on the rods so I couldn't straighten the balance bar when braking pressure applied so itd sit quite wonky.

Sounds like I can overcome it all so good stuff thanks.

Edit, the rod steps in slightly so may not thread properly

[boffer8]

I run AP cylinders on mine so maybe slightly different, but should be able to chop enough of the end to get the balance bar to sit as far towards the bulkhead as possible but still have enough thread to get a lock nut on etc.

Then the final adjustment can be done with the M10 section.

How do you mean you couldn't straighten it when pressure is applied?

[Iain]

Want to follow this guide and when the pedal is applied gently ensure the bias bar is level by winding in and out the push rods.

http://www.wilwood.com/Images/TechTip/Pedal/figure2.gif

To set up the balance bar, thread the master cylinder pushrods through their respective clevises to obtain the desired position. Threading one pushrod into its respective clevis means threading the other one out the same amount. Sometimes this will lead to a “cocked” balance bar when the pedal is in the relaxed position, see*Figure 2, “no pedal effort”. This is acceptable as long as each master cylinder pushrod is completely free of pressure when the pedal is relaxed.

[dan23]

any progress on this ?
those nuts I mentioned are called connector nuts

[Iain]

Made some progress will update my wip properly when done but I've extended the rod down and cut down the push rods of the cylinders.

https://uploads.tapatalk-cdn.com/20151228/09a86bc7e273adc8c57271d52f0460f5.jpg

https://uploads.tapatalk-cdn.com/20151228/0e780016194a64f1334f2b1f8bd2c094.jpg

Now has m10 nuts on to lock the connector off.... :)

It's all mounted in the car and I can get it all connected up side ways on the original hole in the pedal.

https://uploads.tapatalk-cdn.com/20151228/a3a539493102fec9ff749a3f0809d006.jpg

[RallyMarshal]

Told ya....

Glad to see your making progress though. Oh and yes, everything on a rallycar feels as difficult as this does when re-engineering.

Paul..

[Iain]

Apologies for my rant Paul ha ha you spend top dollar on some items and expect them to just fit.

[Benn]

That looks good IaIn.

[mk1nova_rich]

Good work...the reservoir cap looks a snug fit under the scuttle panel though lol

[Iain]

Plenty of room to get it off... It would be touching the foam air filter and need a strut brace re design if forwards.

Lines are in now so won't be long until it gets tested.

[Iain]

It's all in and "functional" but something is hugely wrong somewhere. I cant apply anywhere near enough pressure to give a safe braking distance on the road, let alone enough to bed in the pads or lock the wheels.

It's not weedy legs and having to get used to it before I get a that...

[mk1nova_rich]

Not getting enough travel on the master cylinders?

[Iain]

It gives a nice firm pedal when holding it down stationary so assume they're OK there?

Only thing I can think of is pedal ratio being a cut down Corsa pedal...

[mk1nova_rich]

Do you mean you are physically unable to apply enough pressure? I read it as the setup wasnt applying enough braking force when pedal pressed

[Iain]

I'm not sure which it is in all honesty. Somewhere between my foot and the calipers isn't putting in enough force if that makes sense!

[Edd]

What was a matter with the Corsa set up in the first place?

[Southie]

Are you sure you've got the brakes bled up and there's no air trapped anywhere?

[Iain]

I never had real coincidence in stamping on them late before a corner edd. Probably wasn't the servos fault but just wanted to rejig it and see if I could fine tune it to the point o had confidence in them

The pedal goes nice and firm so that's an indication theres no air isn't it?

[toymex]

When I first fitted my old bias box it was exactly the same ,I am not exactly sure how I got them to work properly ,it was a combination of re bleeding and spacing the rear cylinder away from the box as I think it was stopping the front cylinder from travelling enough to get good pressure to the front calipers .i also manually bled them ,but you must do both circuits together

[Iain]

Can you remember how far you spaced the rear caliper?

I've extended the push rod on the drivers cylinder slightly so the balance bar is straight when applying medium pressure, although I guess there's a chance it could be braking the rears and not much on the fronts. I adjusted the bias all the way to the front and it helped slightly but not lots.

[toymex]

I did the same Iain ,I am not 100% what sorted it but I spaced the cylinder back by about 6 mm ,it was the thickest washer I could purchase ,when you sort the teething problems they work brilliantly

[Iain]

I'll take your word for that lol The set up has short welded studs on too so spacing it won't be easy either, what a pain. Suppose the balance bar could be maxing out angle wise before pressuring the front brakes enough.

[toymex]

They are tricky to get right but when they are you wont be going back ,when you press the pedal check to make sure that the front cylinder is moving first and more than the rear ,I found that it was sort of rocking off the rear cylinder no matter how the bias bar was set ,hence spacing the rear cylinder ,I found spacing easier than trying to adjust pushrods lengths

[Iain]

I'm 99% sure mine is rocking off the rear, which I would have thought is OK as it would be taking the 'path of least resistance' and only start braking the rear when the front has pressure. I guess that's what the push rod adjustment is designed to do.

Thanks for the words of confidence my expensive paperweight will be an improvement.

[toymex]

I think Wilwood have an instruction sheet online somewhere ,if my memory serves me right it says with the cylinders bled and the bias bar in the middle the bar should remain perpendicular to the pedal box ,when the pedal is pressed .I couldn't get mine like this ,the rear would move first ,then it would rock towards the front

[Iain]

The guide said with moderate pressure it should be straight, but I don't recall it saying how it should end up straight I.e. Rocked or not.

[toymex]

Try loosening the rear cylinder where it's bolted to the box so it's loose then try the brakes ,see what they are like then

[Iain]

Will do, the threads aren't very generous on the box though so may be a bit of a pain

[Benn]

When you bled them, did you try by hand (foot) first, to see if you're moving the fluid...

[Iain]

The fluid moves, the pistons have moved back out and cleaned up the discs.

There's no binding of the bias bar and I can't apply any more pressure on the cylinder when the pedal is fully depressed.

Here's a video of the pedal assembly when applying a brake pressures with an incredibly manly voice over


https://youtu.be/BaCkBIFh12E

In total fully depressed:
Pedal moves 9cm
Rear cylinder moves 0.8cm
Front cylinder moves 2.5cm

[toymex]

I haven't got my car ATM to compare but it looks like the cylinder on the left is moving too much ,maybe indicating air in this circuit I would try manually bleeding both circuits at the same time and this way you will make sure both cylinders are moving fluid

[Iain]

Yeah weird as the pedal is nice and firm but I think another re-bleed is in order. Hopefully an easy fix then!

I'll re-pressure bleed them as manual bleeding is tedius. lol

[Iain]

Having read about 'bench bleeding' new cylinders to remove air, I think I'll do the manual pedal bleeding to try and exercise the cylinder.

[Benn]

I was only thinking if the fluid wasn't moving thru it enough when move with ya foot. As you pressure bled it.

[Iain]

The issue was air trapped in the cylinders from pressure bleeding. Wouldn't have had the issue with brake pedal bleeding, or 'bench bleeding' them first (look it up, it's a common thing to do apparently)

I looped the cylinders back on themselves, filled with fluid, and pumped the pedal lots of times so the cylinders were only full of fluid. Then reconnected the lines and pressure bled as before. Barely any travel on the cylinders now, so sorted.

http://iainel.co.uk/images/forums/NovaWIP2b/247.JPG

Just the pedal ratio to look at now...

[RallyMarshal]

I only ever pedal bleed so can understand why its happened but havent ever had that issue..

Paul..

[MARTIN KELSON]

Glad you're getting closer mate.
Double check that ratio & you should be there.

[Iain]

Glad you're getting closer mate.
Double check that ratio & you should be there.
Yep definitely needs the ratio looking at like you said. My foot hurt from standing on them!

Total revamp of the corsa set up to lengthen pedal and move linkage bar and should be better.