terrible pedal travel

Post by **Robins** » Sun Apr 25, 2004 9:22 pm

Hi All
I have a slight problem with me disc brakes. I have just fitted the Ford conversion to my Traveller, obviously with the bulkhead reservoir kit with it (took longer to fit that than the discs!). Fitting was fine, and I removed that little rubber cone thing from the master cylinder like they said, and bled the system correctly. But pedal travel is a shade worrying! The instructions do say brakes might feel a bit spongy for the first 200 miles or so during the 'bedding in' process but mine are bad.
When stationary pedal travels just over about half way down before feeling solid and does hold steady. But whilst driving the pedal travels almost all the way to the floor and then bites on say the last 20-30mm from the floor, and again holds steady. I travelled about 100 miles on Saturday in the hope things would 'bed in' a bit like they said in instructions, but no change at all. The pedal travel shouldn't be this bad should it? I have the same setup on my van but I don't remember them being like this. I'm using DOT4 fluid bleeding the system the conventional way.
Could it be a problem in the master cylinder maybe, possibly worn? The pedal travel was very good on the drum system though, I don't understand it. Any help very much apreciated.
cheers, Daniel

Post by **Peetee** » Mon Apr 26, 2004 8:31 am

Are the calipers centred about the discs? it sounds like one pad is coming into contact before the other. The caliper should have free movement from side to side. With a bit of effort you should be able to touch the disc on each pad in turn.

When stationary pedal travels just over about half way down before feeling solid and does hold steady. But whilst driving the pedal travels almost all the way to the floor

Do you have a servo? Sounds like a servo problem if it's different when the car isn't running.

Post by **salty_monk** » Mon Apr 26, 2004 9:15 am

Servo shouldn't affect pedal travel should it?? Sounds like you still have some air in the system to me as it's not altering so won't be leaking at a guess.
Try using an "Eazi-Bleed" system. They're only about £12 & use air pressure from the spare tyre to really push the fluid & air through.
Bonus to this is you don't need a pedal operator!
My mate couldn't blead his Polo G40 brakes successfully until he bought one of these...

Post by **Cam** » Mon Apr 26, 2004 9:50 am

Sounds odd that. I have the Ford disc conversion on mine (no servo) and the pedal travel is the same as with the drums. Also when it's on it's not spongey at all, it's really firm. It does sound like you have air in the system. Try a re-bleed and see if it improves it at all. Have you bled the rears too?? as if you have had the master cylinder out ALL the brakes will need bleeding (you probably already have but I thought it's worth mentioning just in case!).

Post by **salty_monk** » Mon Apr 26, 2004 11:35 am

Presumably there is a specific order to bleed them in too... can't remember what it is offhand, been a long time since I bled Minor brakes due to about 12 years without one to play with but Haynes or one of the guys'll tell you....
Eazi-Bleed kits are the way forward though... there's a post on here somewhere about them, think he may have had to mod the cap but you should be ok as you have the reservoir...

Post by **Peetee** » Mon Apr 26, 2004 12:53 pm

Polo G40

Mmmmm, nice. One day, maybe.......................

Post by **rayofleamington** » Mon Apr 26, 2004 12:59 pm

Polo G40

Well - it is quite scary how long the early Polo's will last! It seems they followed the same over-engineering principles as the Minor.

Post by **pskipper** » Mon Apr 26, 2004 1:23 pm

My last car was an '82 Polo, I still see her around the area sometimes

Post by **Robins** » Mon Apr 26, 2004 7:07 pm

Hi all, thanks for your thoughts and help.Much appreciated.
I don't have a servo. I thought it was odd that pedal travel was different when moving, usually get that with wheel cylinders that are adjusted wrong. I did bleed the system all the way round twice just to make sure and there was no air bubbles comming out, but I think I will bleed again and might get one of these eazi-bleed things anyway and do it, would I get one of those at Halfords?
I also have the ford conversion on my moggie van and the brakes are spot on, just have to think about touching the pedal and I'm slowing down, this is why I converted the traveller.
The part of the caliper that bolts to the mounting brackets is central over the disc, but the caliper itself slides and grips on this part, am I right? Could it be to much play in the new bearings making the disc wobble, pushing the pads open so more pedal travel is needed to close the gap? long shot I know but the instructions do say only tighten the hub nut finger tight then open a fraction to put split pin through which seemed ridiculously loose to me? This was after tightening to 5 lbft whilst spinning hub and then loosening, then repeating a few times.
It's probably nothing but I also had awful brake squeal as the pedal was being depressed and then after liffting off, more so on the bends.

cheers, Daniel

Post by **Matt** » Mon Apr 26, 2004 7:13 pm

I would say if you can wobble the wheels backwards and forwards, ie. there is slack then the hub is too loose, in my opinion this would affect the brakes, not because of increased travel, but because of the area of pads in contact with the disk.

Post by **Cam** » Mon Apr 26, 2004 7:15 pm

tighten the hub nut finger tight then open a fraction to put split pin through which seemed ridiculously loose to me? This was after tightening to 5 lbft whilst spinning hub and then loosening, then repeating a few times.

I did exactly the same 2 1/2 years ago! and it's still OK after 20,000 miles.

It's probably nothing but I also had awful brake squeal as the pedal was being depressed and then after liffting off, more so on the bends.

It's usually the pad/disc material that causes that. I get it from time to time.

The part of the caliper that bolts to the mounting brackets is central over the disc, but the caliper itself slides and grips on this part, am I right?

Yep.

Post by **salty_monk** » Mon Apr 26, 2004 7:52 pm

had awful brake squeal as the pedal was being depressed and then after liffting off

Normally caused by the pads vibrating against the pistons, smear copper grease over the back of them before sliding into the caliper & it should stop...

Yes you can get an Eazi-Bleed kit at Halfords... Might be cheaper elsewhere though...

Post by **Peetee** » Mon Apr 26, 2004 8:28 pm

The part of the caliper that bolts to the mounting brackets is central over the disc, but the caliper itself slides and grips on this part, am I right?

There is a part of the caliper that bolts to the upright. two long bolts provide the bearing for the caliper proper which slides in and out on these. inside the caliper is a piston that goes in and out too. Ideally the fluid pressure pushes out the piston and one pad comes into contact with the disc. The piston can not move out any further so the caliper starts to move inward (the two are still moving apart under fluid pressure you see). This drags the second pad into contact with the other side of the disc. The advantage of this system is that the two pads do not contact the disc at exactly the same time and the brakes don't snatch. The same system is used by shimano for mountain bike brakes where the springs are made of different steels so they compress unevenly under the same cable tension.

Post by **salty_monk** » Tue Apr 27, 2004 9:17 am

oooh, another Mountain biker, Hopes are better though....! I use the Mini's. What do you ride?

Post by **Peetee** » Tue Apr 27, 2004 2:04 pm

What do you ride

It's a custom built, personally designed 531 rigid (full-sus is for wooses) with XT, M231 and Magura rim brakes. It's a bit long in the tooth now but still cuts it.
I have 5 road bikes too but precious little time to use any of them

Post by **57traveller** » Tue Apr 27, 2004 3:48 pm

It's sometimes recommended to bleed the wheel cylinder that is furthest away from the master cylinder first. So this would be nearside rear(on a RHD Minor). OS rear 2nd, NS front 3rd and OS front last. Don't know if it's any better in that order though.

Post by **d_harris** » Tue Apr 27, 2004 6:18 pm

full-sus is for wooses

Agreed! not so sure about for cars though!!! I'm still thinking of getting some ally wheels for my racer - I was chuffed when I managed to do 22mph along brighton seafront today (not so clever considering how cr*p my brakes are)

Post by **Robins** » Mon May 10, 2004 8:57 pm

Update: Convinced it was the master cylinder at fault after bleeding the system again with no air showing up, I wipped it out and bought a new master cylinder.
I also went to Halfords and got a ezee-bleed kit £13.99. Yes I'm sure it works very well, even has instructions with it for adapting the M/Cyl cap on the Moggie, nice I thought. But I have a bulkhead resivoir kit and the lid for this is to big and also needs adapting to use the ezee-bleed kit, great! Not having a spare lid and unwilling to drill holes in it, I once again bledd the system the conventional way, doing a belt and bracers job I did it twice just in case. I am confident the system is free of air. After a good test the pedal does travel about half way before full travel is achieved, even when driving, a bit more travel than my van but I'm happy with it anyway.
What I don't like is the brake squeal I'm getting, well I say 'squeal' but it's not the sound usually caused by dust in the drums. It's more of a mid to high pitched, smooth and constant vibration, if that makes sence, the noise is definatley comming from the front. It happens after I've been driving a while, so when things heat up a bit I suppoes. It's worse at slow speed when slowing gradual and on a slight bend at the same time and then still after liftting off the pedal until the car straightens up. Any ideas what causes this? could it be just cheap pads that come with the kit?.

cheers, Daniel

Post by **Kevin** » Tue May 11, 2004 9:45 am

(full-sus is for wooses)

Does that apply to your moggie as well Pete

Post by **salty_monk** » Tue May 11, 2004 1:33 pm

full-sus is for wooses

No way... each have their place; as do hydraulic disks. It just lets you do different things & generally go faster. For example a car with good suspension setup & four pot brakes would always be faster round a track than a standard equivalent if power was the same...

I have a road bike too...

managed to do 22mph along brighton seafront today

Try 55mph down the side of the Alps, that'll really get your blood pumping!!