Pedal height

[cheezle]

Hi

My master cylinders are in and bleed ,I haven't driven the moke yet so I'm not sure what the clutch is like ,it does feel ok , I'm really only worried about getting it regoed plus I don't like the look

I did at the time put extra shims under the Brake master to see if it looked any better , 4-5 mm would of done it , I didn't like that the nuts didn't have much thread to grip onto
I will get measurements hopefully today

Cheers
Cheezle

[matpaul]

When I bought my 78 Californian it was pretty much unmolested . The clutch pedal was from memory ~25mm lower than the brake pedal and the clutch pedal would touch the floor (a steering rack U-Bolt nut?) when pressed all the way down. There was no freeplay or worn parts in the system , it worked fine and I assume that it was like that from factory. I have since removed the clutch master cylinder and removed the spacer that it had under the mounting plate (at the 2 hold down bolts). This has brought the pedal up higher but I can't say it has made any difference to the way it operates (I did change the clutch / motor at the same time). I would be reluctant to reduce the available travel of the brake pedal to match pedal heights. I do understand your concern for passing an inspection, if it works properly and that is how the maker intended it to be you would think it would be ok.

[Mokee Moke]

Greetings all,

I would love to post photos to this thread that I have taken of my Moke pedals etc like Cheezle and Incognito; how did you guys do that?

I still have my original tin-type clutch master cylinder, so I will remove the new plastic style master cylinder tomorrow and compare. Pain in the proverbial, but I can't leave it as is.

Will post update, possibly with images for clarity if someone can tell me how to do that.

Cheers,
Greg

[Halfpint]

Hi Greg, I’ve sent you a PM regarding the photo gallery 

HP

[winabbey]

I did at the time put extra shims under the Brake master to see if it looked any better , 4-5 mm would of done it , I didn't like that the nuts didn't have much thread to grip onto.

Reminded me of this Service Liaison Summary dated May 1970 where insufficient thread was an issue.

[Drakman]

Wow, Winabbey, That's gold, where did you find that info?

Dave

[cheezle]

Hi all
Winabbey , Interesting read ,does this mean I need to go back to the tin master 
I pulled my clutch master and duel brake master out last night ,measuring from the face where it bolts down of the master cylinders to the centre of the pin hole.

Dual brake master ( part number GMC227 ) 75.20mm
Clutch master ( part number GMC1008 )  68.20mm

The brake has the 2mm spacer under it so that would bring that back to 73.20mm
I think this is the problem
with masters removed I put some nuts on the peddle box and tightened down, then measured from mounting face down to the peddles they are the same

I wanted to measure the old masters but I think they have gone to heaven ,has anyone got a set of tin can type masters to measure

Greg I haven't posted photos as I need she who must be obeyed to help in this department ,she won't help, showed me once at a million miles hour it went straight over my head ,unless there is something HP is sending you that will help a computer dummy

Cheers
Cheezle

[Halfpint]

Hi Cheezle,
Nothing special from me, I was just pointing Greg to Maddogs guide to posting photos and hoped it might have been something simple I could have helped with. Unfortunately I wasn’t able to help much last night, hopefully we can try again today. I did it by pm as I didn’t want to hijack what is a very good discussion thread about Mokes, not posting photos.
HP

[Terry]

Reminded me of this Service Liaison Summary dated May 1970 where insufficient thread was an issue.

The reference to Plastic Reservoir master cylinders maybe a reference to the original Lockheed/Girlock master cylinders with plastic tanks that were used in the early 1970's and not the aftermarket replacement plastic tanks fitted to the 'tin can' style masters that we are talking about here. As far as I know the 'tin can' were still in use late into the production, the early 80's. 

Terry

[winabbey]

Wow, Winabbey, That's gold, where did you find that info?

Dave

It's part of what keeps me out of trouble in retirement. I search out and preserve any and all documents, publications, microfiche, etc. produced by BMC and Leyland in Australia. They appear on the Ausmini forum, Facebook groups and here as the need arises.

[Mokee Moke]

G'day Cheezle and co.

Ok, so I've had a frustrating afternoon in the garage, but I believe I may have cracked the problem. It seems the brake pedal is most likely at the correct height when at rest (possibly a little high, but not cause for concern), whilst the clutch pedal is around 20-22mm lower than the brake pedal. Incidentally, my pedal heights (taken from the floor to the pedal plate) are as follows:
- brake pedal (connected to m/c) 131-132mm
- clutch pedal (not connected to the m/c) 135mm; 120mm connected to m/c without gasket installed; 113mm with gasket installed.

Without original specifications available to cross-check, its a bit of a guessing game. However, through process of elimination I arrived at the conclusion that the clutch m/c pushrod is 4-5mm too short, which due to the position of the pin hole and the arc that the pedal lever swings through, creates the 20mm height difference.

After removing and reinstalling both the clutch and brake m/c several times, including refitting the original clutch master cylinder, I found if I removed the gasket under the clutch m/c flange (2mm thick) and refitted the cylinder I would gain approx 6mm pedal height. This led to the realisation the pin hole in the top of the pedal lever doesn't need to move by more than one or two millimetres to have compound effect to the height of the pedal foot plate (relative to the floor).

To prove my theory, I tried to swap the brake m/c pushrod with the clutch m/c pushrod and refitted to the car; but alas the new brake m/c retaining washer (holding the pushrod ball in the cylinder) would not fit into the clutch m/c. However, I did note that when I had the two pushrods out of their respective cylinders, there was approx 4mm difference between the ball ends to the clevis edge.

When I installed the clutch m/c in the car without the gasket under the flange, I observed the clevis pin hole was only a few millimetres short of alignment with the pin hole in the clutch lever (whilst at rest). However, to align the two holes, the pedal had to be pushed downwards approx 20mm.

Noting I have tried both the older tin-style clutch cylinder and plastic style clutch cylinder, there is no discernible difference to the pedal height when either was installed.

When I first embarked on this journey of discovery (see another post I have written re changing the brake m/c and clutch m/c) I found the clutch pedal pin hole was flogged out by around half a pin hole. I have since had the hole welded and redrilled back to spec. The pin itself was worn quite a bit too. So, thinking back on it, the wear was enough to allow the pedal to be approximately level with the brake pedal.

So, what next?

Are longer pushrods available for Moke clutch m/cs? Should I try to lengthen the original rod somehow? Should I remove the pedal and file out the pin hole?

Happy to entertain others thoughts and advice.

Best regards,
Greg

PS: I have taken heaps of photos, but I guess everyone here can visualise the issue from there own experiences (and I haven't been able to upload photos)

[cheezle]

Hi
I got new pins when I got new Masters ,they are a nice fit into pedals ,so I'm happy with the wear ,when you look at the holes lining up with the pedal at it rest point it literally is on about 1-2 mm out ,
I haven't pulled the push rod out yet ,
Greg do you think building up the ball end with weld then grinding back into shape would do it
I know this isn't what you want to have to do with new parts ,but the pedals look SH
I was going to ask the licensing inspector if it would mater but i didn't want to bring it to his attention as we only have the one
Cheers
Cheezle 

[Steam]

G'day All
 Just to confuse matters my Clubman pedals all sit at the same height with various reservoir combinations.
older (original) tin brake and older tall plastic clutch
New plastic brake, new plastic clutch (looks like old tin but plastic tank)
I think the document is refering to the old tall plastic masters (as Terry said) which had the large (2 1/2 inch ish) cap rather than the new plastic replacements.

[Mokee Moke]

G'day all,

I believe I have a 'fix' for the pedal height difference issue. I recommend installing a piece of 5mm thick rubber (firm rubber, like a mudflap) on the floor of the pedal cavity in the firewall immediately under the brake pedal lever. In effect, the brake pedal now rests against a rubber bump-stop, rather than the m/c pushrod stopping travel against the m/c pushrod retaining washer.

I remembered last night that when I removed the pedal box assembly (ages ago) there was a piece of rubber mat bonded to the firewall cavity floor, under the brake pedal lever. I didn't think much of it at the time, but luckily I kept it and reinstalled it this morning.

I also replaced the new 2mm thick gasket under the clutch m/c flange with the original gasket (garage made) 0.5mm thick. The effect was to raise the clutch pedal height to 116mm (from 114mm).

BINGO!! Pedal height difference between clutch and brake pedal plates reduced to 7mm:
- brake pedal height (relative to floor) 123mm. A reduction of 8-9mm.
- clutch pedal height 116mm

Not content to live with 7mm difference, I kept building the height of the rubber mat with feeler gauges. As identified in earlier posts, there is not a one-to-one ratio due to the arc movement of the pedal and its pivot point relative to the pin hole. The best result I could obtain was to add a 1mm thick washer to the rubber mat to give a stack height of 5mm. Result:
- Brake pedal height 115mm
- Clutch pedal height 116mm

I can live with a difference of 1mm. It will also pass RWC.

Note; I did consider the m/c pushrod is now effectively not returning to its spec rest position, which could mean there may be an issue with covering/uncovering of internal ports in the m/c bore resulting in sub-optimal generation of hydraulic force. However, the travel 'lost' in the vertical movement of the pushrod is not greater than 3-4mm, which I reckon would have no effect on the hydraulic actions.

Conclusion.
Noting both the brake and clutch m/cs can be fitted to a range of vehicles, I suspect the following:
- brake m/c pushrod is possibly a few millimetres too long for a Moke application.
- clutch m/c pushrod is possibly a few millimetres too short for a Moke application.
- clutch m/c flange gasket is too thick for a Moke application.

Solution (recommendation) Noting the clutch m/c pedal height is the reference datum due to it being the 'lowest' height, I recommend the following:
1. Make and install thin gasket (0.5mm) under clutch m/c flange. Torque to normal spec. Alternatively, smear a small amount of gasket cement under flange.
2. Make a hard rubber bump-stop from 5mm thick rubber mat. If 5mm rubber is not available, then build a stack using combination of thinner rubber mat and washers bonded together.. The key here is not to exceed 5mm total thickness, as the brake pedal will be noticeably lower than the clutch pedal.
3. Bond rubber mat to floor of firewall cavity where the brake pedal lever rests, ensuring it does not interfere with the brake pedal lever arc movement.

Once I can upload photos to the site, I will post photos of the above for those interested.

I hope this conversation has been useful and entertaining. I certainly have enjoyed it 

Cheers,
Greg

[Terry]

Hi,

The issue with not returning the push rod all the way to the normal resting position is that internal ports you mention are what returns to the reservoir the excess fluid to relieve the pressure on so shoes and pads can rest of the braking surface and importantly  to get more fluid when needed which can make your suggested sub optimal  to become randomly non operational.

My experience with this problem was on a single master system and was resolved by replacing the 1-2mm shim under the Brake Master cylinder that raised the height to make sure the pedal pulled the push rod all the way down. It can be quite scary when the brakes randomly don't work with the highlight for me being nearly going under a police horse at about 60kph. The horse shouldn't have been there, but I couldn't stop either, luckily the horses self preservation kicked in and it just got out of the way.

I would NOT recommend reducing the brake piston travel as a solution.

The bit of padding you mention was there when you pulled the pedal box out is usually just a piece of hessian matting, like old style carpet underlay, which the factory fitted there to quieten things down. You can also find the same stuff between the body and the rear sub frame to reduce drumming of the rear tray.


.... ten minutes later

To satisfy my own curiosity I went for a look at a few unmolested Mokes that I have around here to see what the pedals look like from the factory with the original brake equipment. They fell into two groups;

Single system Brake Master with Tin Tank Clutch Master = Pedal Height is the same. Mokes were 1975, 72, 73

Dual system Brake with Tin Tank Clucth = Clutch pedal noticeably lower than Brake Pedal. Mokes 1979, 1980

There was a mix of drum and disc brake front ends that didn't make any difference to the results.


I think people are trying to solve a Design Feature that has always been there on the Dual System Brake masters.

Terry

Ps. I went had a look through ADR 31 and there is nothing about pedal height, relative to clutch pedal or not, it is only concerned about pedal force.