Clutch & brake M/Cyl sizes?

[Talkwrench]

Hi guys , what is the bore size of the clutch master cyl? Would it uniform size throughout the Triumph models, as I have the 2500 6 cyl motor and gearbox in my Herald.
Also the brake M/Cyl bore size. did it vary in the Herald range?

[andy thompson]

Not sure on the clutch master cylinder of a Herald / Vitesse but there are a myriad of sizes for the brakes - and the clutch and brake are very similar (apart from reservoir size).

Btw slave cylinders for 2000/2500 gearbox are either 7/8" or 1" as standard. Most people use 7/8" as standard as its hard to get disengagement with 1" - (less travel)

Chris Witor says master cylinder on a 2000 is 5/8"



   http://www.chriswitor.com/proddetail.php?prod=153183

[heraldcoupe]

Clutch master cylinders on Heralds are all 5/8" bore,

Cheers,
Bill.

[Talkwrench]

As with all things modified there is a trade off...
I ask as it looks like the clutch master cyl is on its way out and the problem Im having is that I have to jam the clutch pedal through the floor to get it to work. Ok, knowing its probably a 5/8 bore would my best bet is going lager like 3/4 or a 7/8 ? It take it that the pedal will be a bit harder to push but the clutch should release better?  
Are these types of mater cylinders marked anywhere for size?
Also the previous owner said they are very easy to find as you can buy them at any trailer parts place cheap? [australia]

I will attach a picture showing the dual circuit setup . Its a very "heavy" pedal it will pull up well but you have to push like hell, I don't think my wife could drive it. I think this may have been a good idea [it was needed for adr]  but practically it doesn't work so well. Again I have no idea of bore sizes here and I would have thought two smaller sizes better?? Or would it still have to be the 5/8 BUT with now double the pedal pressure?? I watched it the other day as I put my foot on the brake and I saw that the rods going into each M/C did not go evenly one was slightly more than the other mmm?  Well I guess it could be ok IF it was the fronts working slightly more??

Thoughts?  

[junkuser]

What you have there is a duel circuit braking system rather than a balancer. If one circuit fails the yoke shaped piece would be restricted in its movement by the shape.

Could be replaced by a normal dual circuit system.

With that system the brake pedal would be heavier as you effectively have twice the  piston area of a single master cylinder acting on the same total slave area as one had been.

There would be a different amount of fluid going into the front and rear slaves so not likely that the rod movement would be the same.

This is assuming the masters and slaves are of original sizes.
You could get away with smaller diameter masters but unlikely to find any suitable.

Power assist would be a way of overcoming the pedal pressure problem if this is acceptable.
Would best be on both circuits but may be OK on front only and of low gain.
A mechanical solution may be better to apply more force to the "balancer" but this would put more load on it and you are getting into danger territory with major modifications to the braking system and the "balancer" may not be strong enough.

Pity the pedal pressure is too high as the basic design is sound for making a dual circuit, if well made.

[Talkwrench]

Yes I agree with everything you said.. I checked the pedal ratio , my god no wonder it doesn't work well , I got 3.5 ;1  that should only be used for power brakes!  Seems all wrong right from the factory?! and its not helping with mods over the top.. I could not see any sizes stamped on the M/cylinders so I may have to pull one and see. From what Im "feeling" I need the smallest 5/8 ones for sure!.
Now I still have the problem with the clutch and having to push it through the floor....mmm what size ??

[junkuser]

The pedal ratio is quite adequate with the original set-up. This is '40s design and we oldies are quite comfortable with it, especially coming off '20s and '30s designs. Your wife may well not be as she is probably used to power assist. (that took some time for we oldies to get used to and I still don't like it, full fade before the feel changes, oops, too late!)

Would be surprised if the masters are not 5/8" as Bill said.

Not sure what the clutch problem is. The original ratio give more than adequate travel in the '62 Spit and I imagine this is the same for your Herald. Stand to be corrected.
The ratio is so adequate in original for that I bored out the slave to give a softer pedal and there is still plenty of travel.
Probably wear in the hole in the top of the pedal arm (if the return spring on the pedal is present), master not filling fully, pivot pin in yoke loose, slave not positioned correctly, adjuster on yoke not set correctly (if you have one off and early Herald. May sound an odd one but have one on my Spit, just fitted to see what they had in mind and have never taken it off.  You never know what you may find on cars that have been through several fiddler's hands.) and lots more.

Mal.

[Talkwrench]

Well all I can say is I drive a 35 pickup that still has the wooden floor in it just about everyday with standard 40' style juice brakes and I have no problems with it.. Maybe the Heralds were a bit hit n miss . I was in a car store yesterday trying to find a new ignition switch for it , the guy laughed and said ohh a Herald hows the brakes on it ?? he apparently tried to get them working better on his but gave up and sold it..  :-/

Yes the clutch did have a bit of play so I made up a bush for the top of the arm, still not great. Well as we know its not original as I have the 6cyl and g/box in it so.. ? Maybe the slave and M/cyl are miss matched , most likely however I need to find out more of what you said about slave not being position correctly , adjuster on the yoke???

Did I read somewhere that bleeding the clutch is a real pain?

I'll be honest and say I haven't been under it yet, simply no room!.

[junkuser]

I have had no experience with Heralds but from what I have seen on this forum the brakes don't seem to be a particular problem if everything is in good condition and set-up correctly as per the workshop manual.

Certainly people do change the system in various ways, such as fitting discs and boosters, but many owners seem quite happy with the brake performance for normal road use, even younger blokes.

The main  thing is to have everything in good condition and each detail in the genuine workshop manual followed.

I hope you enjoy the Herald,
Mal.

P.S. 35 is fairly early for those hydraulic brakes isn't it. What make of Pickup?
They sure beat Ford off the mark.

[heraldcoupe]

9016 wrote:

Maybe the Heralds were a bit hit n miss . I was in a car store yesterday trying to find a new ignition switch for it , the guy laughed and said ohh a Herald hows the brakes on it ?? he apparently tried to get them working better on his but gave up and sold it..  :-/

Not hit and miss at all in terms of operation, however the front drum setup has on occasion given me nightmares when trying to bleed it!
The system itself is sound though, I have owned and driven a very substantial number of all types,

Cheers,
Bill.

[Talkwrench]

Its a 35 Ford pickup with 40 juice brakes. I can lock them up no probs.

OK discovered this today after checking . Brakes:  the right hand M/Cyl is for the front brakes and has a 3/4" M/cyl the left one has a 5/8" m/ cyl...
The clutch: has a 3/4" M/cyl.  

So.  I take it I should be putting a 5/8 M/Cyl for the clutch , that would be the same for the 2500 G/box as well as a Herald?

I have attached some pics of the brakes I have maybe someone will recognise them and suggest why a 3/4" bore was used for the front discs?
I would have thought that 5/8" if standard for disc and drum should have been used for both. I will still suffer as Im working two at the same time though.. But surely this would be better??  

[Talkwrench]

Something went a miss heres the front discs

[junkuser]

Not surprised a lot of brake pedal pressure was required with a 3/4" master.
Whoever did these modifications may have been a bit muddled in his thinking regarding hydraulics, thinking a larger master would give more pressure.

Original clutch master would have been 5/8" also.

Seems like the time has come to check everything in the clutch and braking systems against original specifications for the car.

What model Herald is it? The specifications varied over the years and I, like Bill was taking it to be a front drum model.
Bill's the Herald Guru, so is the man to turn to for guidance.
Providing all the information on the commissioning/compliance plate would be helpful as would pictures of the car from various angles to help Bill pick any other modifications that may have been made.  Not unknown for different body panels to have been blended together.

You will enjoy this car when sorted.

Agree the Ford pickup would brake better with hydraulics instead of rods.
Mal.

[junkuser]

Have just read back through all 21 of your posts Rob and realise you have actually posted quite a bit of information about the car. Sorry for going over the same areas.
Still would be a good idea to put the relevant information in this thread to avoid mugs like me going back over old territory, having not put all the information from the various areas together.
Mal.

[Talkwrench]

Im still learning about the car, I really don't know what is standard and what is not. [ its why i ask a lot of questions  ;d ] The car is modified quite a bit, as you can see it has a motor twice the size of the original.. . I can only remember so much the previous owner said, like.. The front brakes [discs] are bigger , The control arms are heavier, vitesse diff etc . I take that the rear drums are all standard stuff?
Its a 61 and the plate says saloon. Plate might be the only thing left original on the car  :P

I love driving the red devil, scoots along nicely, just would be nice to sort things so my wife could drive it. Im looking into the electrics as well ..sweet lord what a mess!  Ive started installing fuse panels and fitting a temp switch for the  thermo fan, the previous owner had a manual switch, bit late when you realise its boiling over!  ??)

[Talkwrench]

After consulting a brake and clutch shop they think the way the brakes are set up it would be correct with the larger bore for the front discs. My choice now would be to add a booster, so I bought a vh44 ( I did buy two , one for my 35 while at it) ill just use this for the front.
As far as the clutch goes he said that whatever it is I would need to have it sleeved the next size down..

[nang]

Why not get a tandem master cyl and booster from a 2500, I think your's are the same as ours....came fitted from factory. Since you have a 2500 gearbox why not use  2500 clutch hydraulics too ?
Tony.

[junkuser]

"After consulting a brake and clutch shop they think the way the brakes are set up it would be correct with the larger bore for the front discs."

Would be interesting to know his reasoning.
Was the master size fitted specified for the calipers that you have?

[Talkwrench]

More than likely a 5/8 ? Thing that makes me think they might be right is I've found two almost brand new 5/8 m/ cylinders in the stuff that was given to me by the previous owner.

I wonder if a dual m/cyl from a 2500 would fit as there is that " shelf"  on the firewall?

As far as using the same clutch setup.. Well I still think the pedal ratio would be off.

[junkuser]

A possible solution, depending on the cylinder sizes.
The reference to LHD would be for car model identification rather than not suitable for RHD.

You may gather I am not keen on boosted brakes.

http://www.jamespaddock.co.uk/parts.aspx?searchtext=213689

(Thanks to Wimpus on Spitfire section)

[Talkwrench]

Well Id rather not have to go to boosted brakes either , however I think the writing is on the wall.. Mmm that dual setup is kinda pricey! Bought 1/12 boosters for that  ;)

[nang]

I wonder if some of your trouble is the different sized master cyls? It would explain the diff when you pushed the pedal down.
As for your clutch what size slave have you ? 3/4 or 1". There is also an adjustment with 3 holes that the slave clevis can fit into.
Still reckon a 2500 tandem cyl and booster could be adapted to fit for your brakes.
Tony.

[junkuser]

"Now I still have the problem with the clutch and having to push it through the floor....mmm what size ??"

From this I interpreted that you were running out of travel to get the clutch disengaged, which is difficult to understand with the large master, unless the slave is also very much oversize.
Maybe the other possible problems I mentioned are present.

Identifying the calipers and posting would also be helpful in regard to the brakes.  I'm no authority on caliper types, but many on the forum are.

As you have spare 5/8" masters, my approach would be to fit them and see how the brakes feel as a guide to what changes you want.

Keep at it,
Mal.

[Talkwrench]

You interpreted correct. I bleed the clutch and added washers the space the slave forward more, cut the floor matt so I get as much travel as I could and its only slightly better. I could see that a clevis was welded to the push rod there was no multiple holes..  I must have the 1" slave surely...? I couldn't see any sizes clearly stamped on it.

Well I put up pics of the front and rear brakes , so see if some does recognise them..

[heraldcoupe]

9016 wrote:

Well I put up pics of the front and rear brakes , so see if some does recognise them..

The front calipers are type 14, standard fare for Triumphs with engines up to 1500cc.
I'm not sure on the rears, the seven and eight inch drum setups are pretty similar in design. Whatever the size, it's a stock setup, gut feeling is they're seven inch.

Given that this is the same arrangement as used in the 1500 Spitfire, that car uses a 0.7" bore dual circuit master cylinder in it's latest incarnation. I see no need for a different cylinder bore between front and rear brakes - if you feel there's an imbalance, change the rear slave cylinder size to adjust, three different sizes having been used by Standard Triumph in different applications - 5/8", 3/4" and 0.7".

While this should sort out your brake balance, I'd be concerned about using such small calipers with such an increase in weight and performance. Triumph went to type 16s with larger discs for their 2-litre installations, together with eight inch rear drums.

As regards your clutch issue, have you measured the rest position of the pushrod agaisnt the end travel of the slave piston? It may be that your slave cylinder is reaching the stop at the end of it's bore before the clutch has released - no amount of changing cylinder bores is going to alter that. This has become a big issue with the 4-cylinder cars since Delphi altered the clutch design so the rest position of the arm becomes lower.

Cheers,
Bill.