Brake Problem

[Austin-Rover]

Right, Changed the Brake Pads this morning and with the new ones on, the prake pedal is extremely light to touch and the effect the brakes are having is minimal to none - it can only just hold the car still on a slope. What have i done wrong - and what do i need to do to fix it?

Thanks!

:rolleyes:

[GK AutoWorks]

Would help if you bedded them in first. Unfortunatly you have to drive it to do this..

[Jonathan]

Try not to worry too much. I recently changed both discs and pads on 'CHO and it felt awful at first with some advanced planning needed before stopping. After about a week of use (only short runs) the brakes bedded in and everything returned more or less back to normal. I'm pleased I did this job when I did, the old discs had a 2mm deep rim around the edge and some heavy grooving. Dangerous!

[Austin-Rover]

I'm still not convinced everything is okay. The pedal feels like it isnt attached to anything - there is no resistance when you press down on it and it takes a-g-e-s to stop from even the slowest speeds - i certainly wouldnt trust it to go anywhere!

:cool:

[e692wtt]

I presume you've 'gently pumped' the brake pedal to bring the Brake Pads into their operating position? Notwithstanding, I've had the same problem with new pads on my Monty in the past, and it's a case of 'super anticipation' to allow yourself as long as possible to stop, until the Pads 'bed in'. Not fun. Mind you, when I've fitted EBC Greenstuff Pads this hasn't been a problem although the brakes are not as good as 'standard' when they are cold (ie not been used for a bit) but are BRILLIANT when warmed up.

Stick with it, I think that's the answer. They WILL get better with use.

[Mat_C]

If you only changed the front pads, have a good look around for any brake fluid leakage from the pipes/caliper etc. Perhaps the brake line was accidentaly stressed?

Only thing I can think of other than they need bedding in.

[Bertybassett]

RD Gelder

They need to bed in first. All cars have this problem when you first put new pads on. The glaze has to work off so that friction can develop to cause braking. :)

[Simon]

The only other thing that occurs to me is if you have undone a bleed nipple in order to push back a caliper piston, then you might have accidentally admitted a bit of air into the system causing long travel on the pedal and exactly the same symptoms you describe, so you will need to top up the fluid and bleed the brakes. I always use a pair of waterpump pliers to push back the caliper piston when doing the front brakes.

[e692wtt]

While the brakes were apart, did you lubricate the 'sliders' for the Brake Callipers (hidden under little rubber boots)? The brakes are called 'single piston sliding calliper' on our cars because there is only one Brake Piston (moved by the Brake Fluid) and the Brake Pad not pushed out onto the Brake Disc by the single Brake Piston is moved onto the Brake Disc by a 'carrier' which moves on 'sliders' as above - it's actually more complicated than this because this mechanism centres the 'carrier' over the Brake Disc - see below - including the Brake Piston's operating position.

It's possible one of these 'sliders' is sticking and the 'lost movement' in the Brake Pedal is the 'carrier' on the affected brake being flexed as the only available option as the 'slider' is stuck and so the brake pads on the affected axle cannot move normally to take up this 'lost movement' on the 'carrier' via the 'sliders'.

Does this make sense?

I doubt this is the problem as the car is nearly new, but it might be worth checking - abd it will certainly affect the older cars owned by many of us.



Don't try this at home without pressing the Brake Pedal to get the brakes back afterwards, but...

I was checking Monty's outer cv joint rubber covers and wanted to remove one. "Oh," I thought, "I'll lever it off againt this bit of metal in the front axle", did so, changed the rubber cover, put it all back together again, drove off and the brakes didn't work... hmm, went home and changed my underwear after pumping the Brake Pedal enough times to get the brakes back. I'd been levering against the Brake Piston and had moved the Piston on its 'sliders' (see above). While this can be done to check the 'sliders' aren't seized, and is worth doing when you are servicing the car (every 6 months?) press the Brake Pedal afterwards to get the brakes back. Oh, and Daz didn't shift those stains!!!:laugh:

[E_T_V]

My guess would be air has got into the calipers.. Bleed them all (not just the fronts) in the correct order and see what they are like then.

[wemyss]

Your'e quite right in being concerned Richard and I certainly should not attempt to go out on the road with the symptoms you describe.
Yes brakes do get better with bedding in but certainly not to the extent you describe and in some cases is hardly noticable.
With the pedal feeling so light it suggests air in the system as previously posted.
What happens when you pump the brake pedal up and down. Does it tighten up and then feel normal. if this is so it would mean air in the system and repeated pumps will compress it. If so bleeding is the easy remedy.
If not I would suggest you have a mechanical problem and could range across many things including the master cylinder.
Take great care.
nick

[Simon]

The only other thing that I would add, is that it is recommended that one changes the brake fluid every 2 years or 24,000 miles because brake fluid is hygroscopic, in other words it absorbs water. This leads to possible corrosion and other problems. Why not renew yours, which involves bleeding anyway? Invest in a "Gunson's Easibleed" they are excellent and make brake bleeding almost fun.

[Austin-Rover]

Well this morning i beld all the brakes with a Gunsons kit, and there was plenty of air in the system! No wonder they were not working!

All good as new now tho. Thanks for all the ideas!

Next stop, the MOT station.

:cool:

[maestromad]

just got myself some new pads of ebay, I have some disks too. I want to change the pads and disks as they are both past it.

is a disk change likly to be a struggle? Im not too woried about pads they sound idiot proof from what ive read. is there anything else i should consider getting a new replcment for whilst im in this area?

Any help appreciated

[E_T_V]

I think the only tricky bit is getting the disc retaining screws out. They can be a struggle and often have to be drilled out. Not a major task but just annoying.

[Simon]

My disc retaining screws were quite loose but rust between drive flange and disc meant that getting the disc off was a bit if a struggle. Ensure that the mating flanges are critically clean otherwise the disc will go on wonky and you'll get brake judder.

[H48HPE]

Ive got to do this too, Im determined never to have a garage do anything on my car again because you never get what you want. This business of drilling retaining screw out sounds like potential to have a nice undrivable mess on my hands though, hopefully its not going to be a problem when I do mine. Im also going to renew my back brake shoes and wheel cylinders. I recon changing the shoes will be easy but what about the cylinders? any top tips/ things to look out for with those?

[MaestroMatt]

Originally posted by maestromad
just got myself some new pads of ebay, I have some disks too. I want to change the pads and disks as they are both past it.

is a disk change likly to be a struggle? Im not too woried about pads they sound idiot proof from what ive read. is there anything else i should consider getting a new replcment for whilst im in this area?

Any help appreciated

Even though you gazumped me on ebay at the last minute for those Unipart pads, I will give you the benefit of my experience just to show there aren't (m)any hard feelings

The pads can be changed in no time - just undo the bolts on the calliper and slide them out. You may need to push the calliper back in a bit to accommodate the thicker pads as they will have adjusted to the old ones, but this isn't too tricky. I think I just used a big pair of pliers. Be careful that the brake fluid level isn't raised too high by the action of pushing the callipers back - if you have been topping it up on a regular basis, it is possible that you will have to siphon a bit out of the master cylinder to bring it back down to max level.

The discs can be a sod to get off - the screws may shear and require drilling and re-tapping (an impact driver may well budge the obstinate ones, but may equally well shear the head off). I had to re-tap one of mine. The discs will probably, as Simon says, be rusted to the flange and require some encouraging with a club hammer, a power drill on hammer-only action, or a clutch-puller (I used all three before one of mine came off).

Best of luck with it...



Originally posted by H48HPE
This business of drilling retaining screw out sounds like potential to have a nice undrivable mess on my hands though, hopefully its not going to be a problem when I do mine. Im also going to renew my back brake shoes and wheel cylinders. I recon changing the shoes will be easy but what about the cylinders? any top tips/ things to look out for with those?

Drilling out the retaining screws is actually very easy, and re-tapping is also easy if you have the right equipment. Literally impossible without, I should think. Those screws don't take any real load, as the wheel bolt things take all of the rotational force. They are there simply to hold the disc to the flange until it rusts there. You won't render the car undriveable.

I have changed rear shoes and it is a nasty job. You'll need a fixing kit which contains all the springs etc for each side (from Halfrauds) in addition to the new shoes and pistons. Once you have forced your way into the drums (budget two or three days for this simple task), it is pretty easy to follow the instructions in Haynes and fit the shoes. The hardest bit is stretching the springs to reach their holes. I wouldn't ever do the evil job again - I have just bought new drums from Ledders that come complete with all brake components ready fitted and simply need bolting on.

If you are still keen, I may be able to help you out cost-wise as I have a brand new pair of pistons and one new Halfrauds shoe fixing kit that I don't want and which I can sell you at a bargain knock-down price.

[E_T_V]

Rear shoes are easy to change. Although I'm betting they won't need changing as they last forever. Mine were still almost new after 100k miles
However the rear brake cylinders can leak (which is why I replaced my shoes). If you can manage to undo the brake pipe from the cylinder the job is easy. Don't bother with the fitting kit unless your springs are knackered. Changing a set of pads should take about an hour, or maybe two if it is your first time. Shoes the same sort of time only it is messier.

Discs I've not done yet but assuming that you can get those little screws out they should be easy enough, however make sure they need changing before you spend time, effort and money doing so, as I've not needed a new set yet! Just remember when you fit the pads to file/wire brush off the lip or rust that forms on the edges of the discs.

[G Force]

Hi, Heres my tips 4 what its worth :)

Front disc retaining screws are best tackled with a good impact screwdriver with a good correctly fitting screwdriver bit. Give the screw a shock in the clockwise direction before undoing. ;)

Rear w/cylinders, use a hose clamp on the flexy hose ( or gently clamp with mole grips ) to keep fluid loss to a minimum and make bleeding easier. If you have got copper/kunifer brake pipes, it is more likely than not that the pipe will stick to the union, so the pipe will twist when undoing it. to avoid this first loosen the pipe union with a brake pipe spanner or a good quality spanner so not to round it off, then take out the w/cylinder securing bolts and screw off the cylinder instead. :)

Simple but could save time and money in the long run.

Cheers gary ;)