Newbie Here - Need to Pump Stag Brakes

[ianmowcop]

Helo,

I am new to 'classic cars' although I drove them as a young man before the were considered classics!

Jus bought a '74 Stag.
Drives v.well but, the brakes are more effective if pumped once or twice.
If engine at low rev's they are worse.
After pumping once or twice, then released, the sooner the brakes are used again the better they are.

Any ideas please?

Ian

[Andrew Lacey]

Ian,

Could be two things,  has anyone done anything to the brakes recently? as if they have there could be air in the system. If so you will have to bleed the system to get rid of any air.

The other thing which is more likley as you have recently brought your stag, it may not have travelled many miles over the last few years. If so it can cause the rear brake self adjusters to sieze  through lack of use.  To test, apply the handbrake so that it lightly applys the rear brakes, then test to see if you still have to pump the brakes as before. If by applying the handbrake to take up the slack you dont need to pump the brakes that is where the problem may lie. (The first time you try you may have to pump the brakes, as you need to take up the slack then after it should be fine)

Let us know how you get on

Tina

Welcome to the world of Triumphs
   8)

[Roy S]

If you need to bleed the brakes I'll describe the method I was given after nearly 2 litres of brake fluid was used to get an air bubble out.

After fitting new slave units to the rear of my MGB I could not get air out of the system and the brakes had to be pumped to get them to work. I bled them so many times but the air I found out just kept travelling back when the foot pedal was released and not out of the bleed valve.

Method I was told to do was to get the person in the car to pump the brakes until the pedal is solid then undo the bleed valve on the furthest valve from the master cylinder, they keep pressing the foot pedal while you do this. Take care as it will be under pressure and when done close the valve and get them to pump the pedal until hard again then repeat. Keep going until the fluid is clear with no bubles in it. Then you move onto the next wheel.

[ianmowcop]

Tina/Roy

Thank you for your tips, they seem sound and I will use them.

I will let you know how I go on however I am busy decorating (hate it but needs must at times) and, more painfully, a front wheel bearing collapsed at the weekend withot warning!  Enter the AA or, more correctly these days, a sub-contractor.

Ordered 2 x front wheel bearing kits from James Paddock in Chester for £26.50 delivered so, pleasantly suprised by low cost of spares so far.


Attached pic' of Stag.
It (unfortunatly) has a Triumph 2500TC engine on standard Stag gearbox with overdive.
Made the car affordable and, I consider ,more original than Rover V8 (don't start that old chestnut).
I have dream of replacing it with an original engine but that isn't so easy or cheap as wheel bearings! sigh.

Again thank you I will keep you posted

Ian

[Andrew Lacey]

Nice looking stag 8)  They always look good in white.

We changed both front bearings and they were not to bad to fit. we also find the parts quite reasonable priced.

Hope you have great enjoyment from your stag :)

Keep us updated

Tina

[shenderson]

Ian

I was going to suggest that you check the front wheel bearings as slack in them causes the disc to move and push the pads back in, meaning you have to pump the pedal every time.  However with your new bearings all should be well in that area.  Incidentally I believe this occurs in any case, to some extent, due to flexing of the stub axle.  Nothing can be done about that unfortunately.

If the pedal can be pumped up it is more likely a case of adjustment - the "self-adjusters" at the rear are not very effective anyway so I periodically adjust mine manually.

If there is air in the brake system the pedal will feel spongy (easier to feel without the servo working).  If there are still problems after trying all the other tips, here are a couple more (but try the others first).

Remember when bleeding that, unless you have a special tool to hold the shuttle valve central(in the engine bay on the nearside front wing), you either have to bleed one brake from each circuit (i.e. one front and one rear) simultaneously, or make sure your assistant is very careful not to press the pedal too hard when bleeding.

If the shuttle valve does move it's not the end of the world (you will know because the big red warning light on the dashboard will come on brightly) - open a brake on the opposite circuit to the one that was being bled when the light came on and press the pedal hard until the light goes out (but not too hard that the shuttle goes the other way!)

Pump up the pedal and rig up some device to hold it down firmly - e.g. a length of broom handle or similar wedged against the front of the seat - and leave it overnight.  In the morning, get your ever willing assistant to press the pedal down, without releasing the pressure when transferring from broom handle to foot, while you open a bleed valve, then bleed the rest of the system again.

The pressure compresses the air bubbles and they seem to gather in a small numbr of large bubbles rather than hundreds of tiny ones.  It doesn't always work, but worht a try.

The best way to bleed brakes is a bit laborious but saves lots of waste fluid (and cost!) especially if the entire sytem has been drained.

Ideally raise the entire car onto stands and remove the wheels, and rear drums.  Release the self adjusters, open the bleed valve and push the pistons in as far as they will go.  At the front, open the bleed valves and push the caliper pistons in as far as they will go.

Bleed both circuits, starting with hte furthest away from the master cylinder.  You will probably have to go round the system at least twice.

The idea is that by pushing all the pistons in you minimise the volume of  any spaces in the cylinders where air can accumulate.

Finally, it is a good idea to replace all the fluid every 18 months or two years, because it absorbs moisture from the air through the breather.  Apart from minimising the risk of vapour lock, you also minimise the risk of the cylinder bores corroding and starting to leak.

Good luck!

Steve

[ianmowcop]

Tina/Roy/Steve,

Well after, more or less, finishing the decorating and taking a break in sunny Cornwall last weekend I got to tackling the collapsed wheel bearing.
Wheel much looser than I anticipated as I released wheel nuts.  Wheel and hub dropped off as I pulled wheel off.  Stub shaft broken!
So, Steve your theory of, stub shafts flexing causing need to pump brakes maybe explained here if this was a crack opening in the shaft?
Did some damage to hub where bearing seal fits so will need replacement hub too.

Bit scary stub shafts breaking!
Found another thread on here on a Stag rear one breaking.
Anyone any experience or, more importantly, why or how to prevent it?

Ian

[Andrew Lacey]

It seems to me metal fatigue, normally can be caused by high mileage. Stub axles should not flex.  So I would not worry about this being a common fault.

hopefully! once you have replaced the hub etc problem solved.

Best of luck

let us know how you get on

Tina

[ianmowcop]

Well.
Replaced stub axle with secondhand one for a very reasonable £12.50 delivered.
Bled rears and out came loads of bubbles and manky old fluid.
Bled front, same again.
Feeling good.
Now we have different symptoms!
Brake pedal is unpredictable.
Sometimes ok.
Sometimes pedal can go frighteningly low.
Under gentle braking need to follow pedal down to keep same amount of braking.
Getting replacement vac' tube tomorrow as existing one is full of cracks.
I'm suspecting servo is leaking vacuum - any ideas anyone?

Ian

[ianmowcop]

Hey I'm talkin to myself here!
Talking to work colleage, who has more experience, he advised that it's not vacuum leak as engine would not run properly because inlet manifold cannot maintain vacuum to run properly.
It is master cylinder seals.  Likely that I disturbed 'bits' at bottom of resovoir and they are now spoiling the seal or the action of long pump strokes finished off an alredy worn set of seals.
So, master cylinder refurb' kit is on order and master cylinder is off the car and on the bench waiting,

Ian

[Andrew Lacey]

Don't worry we are all here ::) your not talking to your self, we went down to Beaulie at the weekend, there was a mini cooper show on when we were there. Have been busy because the sprint needs our attention, starter motor packed up. Its our daily car so quite important.

Yes you are probably right could be your brake master cylinder, we went for a recon one, as ours looked abit suspect after stripping it down, it was quite a akward job. The final circlip is abit of a pain to get out.

Best of luck

as always let us know how you get on. Sorry I have not been of much help

Tina :)

[ianmowcop]

Tina,

You have helped
Wasn't me whining there - just joshin' 8)

Beaulieu?  Many years since I visited.  Was static then with all cars kept in, what seemed like, a laboratory.
Being a day-to-day car I assume you got a service exchange starter motor?

Oh Yes! I now have the sharpest brakes this side of the equator!

You are right; the inner circlip is out of reach of your average circlip pliers.
I used two jewellers’ screwdrivers with a short piece of rubber hose as a pivot and a pair of pliers to reach that little monkey.

Personally I found replacing master cylinder seals easy and rewarding – for £15 I recommend it to anyone with ‘spongy’ brakes or anyone who wants to overhaul brakes that have only had pads and shoes fitted for the last 10 – 20 years,

Ian

[wakaday]

I was gonna say to swap out your servo and master cylinder for  one from a 5 series BMW. Its a good mod and makes the brakes sharper with less pedal effort.