Manky Monkey Motors

As the title sez!! I got honda shadow trike swingarm reliant axle drum brakes,the back brakes have been constantly sh!te since I got it converted back in 2010.
I have done bike m/cylinder,I have done car M/cylinder god knows how many different pedal/cylinder linkages and pipe convigurations and every year I just about scrape through the MOT.But rest of the year I run around with only a front brake and handbrake.
SO if anyone can tell me how to get me back brakes to work without spending 200 nicker on a disc conversionPLEASE do tell me!!!!!!!!
would be very grateful for any advice.
heres the beast in question.

is it a hydraulic problem or could it be a hard brake lining/poor material,are yours the old sliding cylinders and if so are they sliding. very nice trike by the way

what part of the country are you in ,,

Can you be a bit more specific as to the particular flavour of 's**te' ? Are they too stiff to push with little travel , too little results when you brake etc.? What m/c bore and pedal ratio are you currently running? Also have they checked the handbrake at MOT time and how is that efficiency?

You don't say what ratio brake lever you are using or master cylinder bore.
I think that most bike pedals are about 4:1. Car ones, tend to be 6:1 or more. This gives 50 per cent greater leverage and a corresponding higher line pressure.
I have a pedal ratio of just under 6:1, with a 5/8" master cylinder and can lock the rear wheels without too much effort.

Had the same on me gl1000 trike. kept the std rear brake peddle to reliant drum brake s**t, so I scrapped them and fitted mg midget back plate and brake setup with reliant drums, they work not as good as disc but 99% better than reliant  ;)


these from a mini may work check your drums for size
http://www.ebay.co.uk/itm/261385789881?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I assume you've turned the axle over? Of course you have. Did you then reverse the backplates? You need to have the bleed nipple at the top of the cylinder, there may be other ways of ensuring this (just swapping cylinders?). I'm no expert on reliant rear brakes but they are essentially very simple, and similar to mini rears, you might find mini cylinders slot in, in which case you have a wealth of selection of sizes.
Let us know how you get on.
Huw

I personally think its more to hydaulics than owt else my present master cylinder is off a pan european with reliant slave cylinders on the drums,but I have also tried a "leyland" Mini type master cylinder,
I struggle like fucg to get any pressure when trying to bleed the system,and what little pressure I do occasionally manage barely works the brakes.and it gets scary when that front wheel locks up.
Spanners I,m in North Wales ???
Kapri,I,m getting full travel on the pedal to the master cyl pistonI.E its pushing in far as it will go.dunno wot size bores etc that stuff baffles me.
O,N, Ratio aint got a clue but I just welded an extra inch on the lower side of me pedal cos someone sez it might help but trying to bleed the brakes I cannot get any pressure.
Terry thanks for the info mate but I cannot afford them nice as they look if,n I was gonna spend that money I,d go the whole hog n do a disc job on it.

axle has been flipped slave cylinders are at the botton of the plate on each side,one prob I think I may have is that master cylinder is mounted lower than slave cylinders.

The axle don't need turning over for the Hondas drive rotation is the same as a reliant

Have you tried reverse bleeding through the brake nipple using a syringe, or pressure bleed ezi bleed do one connect up and us the air from a spare wheel to pressure it up

Runback is a common problem with caterham type kit cars, I've read there is a valve you can fit to prevent fluid running back into master cyl. Carbuildingsolutions.com
Please make sure the bleeder is at the top of the slaves. If long travel is the problem you need a larger master.
Huw

was just assuming with the axle it was done by a profesional company I dont know.
Not sure what you mean by bleed nipple on top, cylinder is at bottom of plate and nipple/pipe are side by side at the bottom of the back plate.
are these what you mean,
http://www.ebay.co.uk/itm/161014735163?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Does your brake cylinder look like this

http://www.ebay.co.uk/itm/350972285466?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Pan European has a single rear disc. This requires very little fluid movement to work correctly. The Reliant slaves will require much more fluid.
The fitting of a residual pressure valve mounted close to the master is always a good idea if the master cylinder is lower or a similar height to the slave cylinders to prevent bleed back.

Terry YES those are exactly what I fitted last summer,
O.N.I understand what you are saying but I have also tried this,
http://www.ebay.co.uk/itm/TRIUMPH-HERALD-SPITFIRE-CLUTCH-MASTER-CYLINDER-GMC205-/360181436507?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item53dc7c905b
but cannot get a pedal linkage to work it properly,so its good linkage sh!te brakes cos of hydraulics or s**te linkage s**te brakes becos of linkage cant friggin win.

Sorry , flipping axles over to work with reverse rotation is new to me ( not atrike guy) but i know my way round brakes . HAve you flipped the axle and if so have you moved the backplates around ?

To work the rear brakes you need a 5/8 m/c and a minimum of 4:1 ratio ( as Old Newbie said )though 6:1 would be better a sit will give even more line pressure and slightly more pedal travel ( and so easier more controlled braking ) . I'm not plucking figures out of the air on this or guessing, been on training courses etc ;)

That set up will provide enough line pressure and volume to make them work IF the rest is set up correctly . The pushrod has to go into the m/c at a certian angle or you will lose line pressure due to vectoring .

If you haven't rotated the brakes backplates side to side and top to bottom then the brakes WILL be crap as leading shoes and edges will be all wrong.

A photo of your current pedal set up and rear of rear brakes wouldl help.

Got reliant drum brakes on my Kwak GT550 trike, they lock the rear wheel no problem!  I have a Girling ⁵/₈ master cylinder (landrover sorta thing).  You can just about see it at the bottom of this pic.

Agree with kapri, a pic of the linkage set up when using the "Triumph" Girling master would be helpful. At 5/8" it should be OK if you have suitable linkage ratios.
 Personally, I prefer a direct acting setup (pedal to master) but realise on conversions this isn't always easy to do.
One other point worth mentioning, If you are not using flexibles on the slaves, (Reliant didn't) then the brake pipes should not be clipped or fastened to the axle/frame, within about 16" of the slave cylinders, to allow flex and the cylinders to slide in the backplates.

Welding an extra inch on the bottom will reduce the ratio, not increase it. You can read about ratio here........http://www.mankymonkeymotors.co.uk/forum/index.php?topic=8335.0

A quick google seems to show that the stock pan european rear master cyl is only 1/2" bore size.
This gives a surface area of 0.196 sq inches
300psi (working on 50psi pedal pressure @ 6:1 ratio) / 0.196 = 1530 psi = plenty of pressure but may impact volume of fluid working on the wheel cylinders.

I think that it also has a short stroke. The 5/8" Girling in front of me, has a stroke of 1 1/2" (38mm).

Terry YES those are exactly what I fitted last summer,

When you changed them, did you make sure they moved up and down freely before fitting the brake shoes

on your linkage you can you an idler to change ratio or direction of pull etc to get your girling type m/c positioned where it will work

Argh ??? so many numbers,I cant do numbers ;D
right I done a sketch of my brake pedal set up its terrible but shows roughly how set up.
now its all in straight line with about 2ft bar between pedal and M/C{Red}
to use L/rover M/C I have to rig up a linkage and levers from front of bike virtually to back axle and there is 2 much play and leverage doing wrong things for it to work.
hope you can see my scribblings ok.

how heavy is the bar 2ft seems quite a lot when the bar is in compression.have you watched if it flexes when you press hard on it? move it to above the pivot and use an idler to change direction and height,may also work for the l/rover mc

Bar does not flex,but there is some movement where bar is bolted to M/C rod.

Sorry do not know what you mean by an idler.

Well from your picture, the original pedal looks quite long, thats good.
You need to change the master cylinder. Larger bore to increase fluid volume n longer stroke to push the fluid further.

Why is the m/c on the back axle ? If it connects direct to the pedal you can see what is heppening ,no pushrods or idlers required ?

Possible set ups if you have to fit the master to the rear.
1 is a definite no no ! but I have seen it tried.
2 is sort of ok if the rod is not too long.
3 is the safest.

A better solution is something like this. It would keep the MC clear of the exhausts & make checking easy. Perhaps on a bracket mounted on the foot peg/brake lever mounting.

In ON's diagram no 3 uses an idler to change the direction and ratio of leverage the pedal applys to the m/c

Exactly what I would do Dave !

I'm struggling with how this gets so complicated as Reliant have done the job for 'you' surely ?. Brakes work on a Reliant so fit same m/c ad pedal ratio and it will work again ??  Only difference is the pedal will travel slightly less as it doesn't have to move fluid to the ( single ) front brake as well.

This seems to be a regular problem, mainly on converted bike trikes, where trying to use the original brake pedal and finding a way of mounting the MC, are not fully thought through. Even by some, 'professional trike builders'. ::)
Reliant rear brakes should be perfectly adequate for most bike trikes. I believe that the now famous, disc brake conversion, was originally done for aesthetics and the 'why not' reason.

My setup is more or less as number 3.  I've never had problems with it till I had the brake linings renewed recently and the pedal wasn't set up right and the brakes kept locking on.  Sorted now.

O.N. what you say is very true and is indded my problem,There is no where near the pedal to mouny a M/c,and where i am mounting them the linkages back to the pedal are far to long a with too much play.

not sure where the free play would be coming from.
Was your bike a drum brake model?  If so the standard rod linkage (modified) should be OK when used with a bell crank (idler) as in diagram 3.
You shouldn't need much space between the pedal and frame to forward mount a MC. Having said that making a new pedal may make it easier.
I think is should be possible  to fabricate a suitable mount, between the footboard mounting point and the frame, but without seeing the trike it is difficult to judge.

This problem habitually rears its troubled head! but fortunately there is a deal of clear thinking on the subject,here, as illustrated here in this current diatribe, but a synopsis would be...Reliant did not install a rear braking system on their vehicles, not for it to work!! it was also capable of satisfying the MOT requirements of the Reliant as a car, both 3&4 wheeled variety, capable of carrying,(and stopping!),up to 4 Adult passengers, so..............replicate the Master cylinder configuration, as per original, and "Bingo", simples. I have installed a few trike rear ends using this philosophy, and like BG, no probs. I have also installed the disc brake conversion, which is also OK,looks higher tech. but frankly is no better,or effective, in my estimation, than the orig. drums, for a trike! So folks, stop trying to reinvent the wheel, back to basics as per "Mr Reliant Robin's" system, and it WILL work, honest ;) ;) ;) ;) ;) ;) ;) ;)Morrag

I'm not alover of rear brake conversions but seems to be the 'hot ticket' on most vehicles out there ? Under heavy braking something like 80% plus is done on the front of the vehicle due to weight transfer . However this becomes 100% if the rears aren't working ! LOL

Main adavantage of discs over drums is fade resistance but ,as Morrag says, I reckon it's overkill on a trike which usually weighs about half a Reliant.

As you'll discover Mr Kapri - you need the rear brakes on a trike to work cos if you brake hard with front brake only, the rear has a worrying tendency to try to overtake the front!

 :o

I still have lessons to learn re trikes Bobbi  ;)

built quite a few trikes now, and absolutely agree with morrag on the above,,,,

Yeah, you're right, when I came up with the Vauxhall/Golf disc conversion for Reliants, it was mainly for it's looks & partly because I could. They are indeed about the same efficiency as the original drums, (which are Mini units aren't they?).
I haven't built a trike for a few years now so haven't put one through the MSVA, but my last couple had linked brakes, (the original draft of the MSVA regs called for all trikes to have linked brakes, though this was later removed). As Bobbi says, the majority of the braking needs to be done with the rear brakes -if the front wheel locks up, you lose your steering. For that reason I used to deliberately under brake the front end by removing a disc if 2 were fitted & using old 1970s calipers which were less efficient. Having since discovered brake bias valves, that would obviously be the sensible option. Set all 3 brakes evenly for the test, then re-set with a rear end bias afterwards, (bearing in mind adjustable valves have to be locked in one position for the test).
Too much speed or over braking into a corner will see your 2 rear wheels pushing your single front wheel straight on, across the corner & into the ditch on the other side -if you're lucky. Into the oncoming tractor if you're not. Trike riding's nothing like bike riding. They all behave differently, so be very careful on those maiden voyages chaps until you get to know your particular steed's limits.  ;) 

On the car BIVA test the fronts MUST lock before the rears ,strange things these trikes eh ?  ;)

Well all, thanks for your comments and advice,I have over the past 2 days with much head scratching,grinding and welding and grinding again managed to fit a Girling M/C to the foot plate right next to the pedal and have rigged up an idler set up,I am getting 2/3rds travel on my pedal and full travel on the rod of the cylinder,
I still have to get it all piped up and the brakes adjusted and bled,but based on Morrags previous comment I have done as he suggested and got it as near to origional system as I can.
I should have took photos while doing it but me head was twizzled trying to work it out.
have done a sketch for you,
All you see is UNDERNEATH the footplate,Red M/c obviously,Blue steel plate,Green Idler ,Yellow brake pedal..
Hope you can understand it.

Hope that this works for you. With the MC so low a RPV might be a good idea. Do you still have enough ground clearance?

Narrow motorcycle tyre combined with two big disc brakes and a wet greasy roundabout. Not a fun learning situation.
Personally I wouldn't fit linked brakes unless I had to. Thought about it for a while but I like the flexibility of independent front and rear brakes

O.N,Yeah it is only just higher than the frame at the front,it is still lower than the slave cylinders so I will probly need to fit a one way valve of some sort.
The shaft on the M/c is getting full thrust  and there is minimal play in the Idler so fingers crossed it will do what its s'posed to.
Thanks again to all who have commented/contributed to the post.

OK,I got one more question guys,
Where on the back plate is the optimum place for the slave cyls, when I first got this back from the builder he had mounted them at the top,
I was told by some one that they work better at the bottom of the plate so have since moved them.
I am thankful of any?advice that comes my way so which is it ToP? Bottom? front or rear???????

Cheers All.

As long as the piston is pushing toward the leading shoe, I can't see that it matters. Even that should not matter if the slave is free to slide in the back plate, but they can seize if not maintained correctly.
 I have mine mounted at the front with the hand brake actuating lever hanging down. This gives me easy access to the adjuster from the rear, easy routing of the hand brake cable and also means that if the slave jams in the back plate I still have leading shoe braking.

If reversed from side to side and single action piston then they are as good as when reversing ie rubbish as they are designed to self servo when operating in normal direction of travel .  Double acting brakes it won't make any difference. I don't know which Reliant is though.

as ON has it is the way they are standard also the way mine are and seem to work ok although not road tested as yet

They are, of course, single leading shoe rear brakes, therefore the result is self explanatory! and " as it says on the tin", it matter not at all which way round the shoe/backplate relationship is, Morrag

Thanks Guys!!! ;D

Mine viewed from the front.

Same shoe will always lead ,yup agree with that . But in normal position ,viewing drivers side from curb, then leading shoe is to the right and wheel is rotating clockwise. So as brake actuates show is pushed towards drum by direction of wheel rotation.

Swap the drums side to side and again view the driver  side . Now leading shoe is at rear but wheel is still rotating clockwise. Brake actuation now pushes shoe back to starting position.

EDIT  http://en.wikipedia.org/wiki/Single-leading-shoe_drum_brake

EDIT http://en.wikipedia.org/wiki/Twin-leading-shoe_drum_brake


Yup, understand the SLS set up now , was missing the fact that trailing becomes leading when reversing :oops: