Hi

I have Fiat Punto mk1 55 1996 that was sat in my Dad’s garage for the past 12 years. He never used it much and it was always garaged after he used it. It only has 14,000 miles on the clock from new. It’s in good condition apart from a few paint scratches where he’d hit the garage wall (he gave up driving at 85 thankfully). The Punto had sat there collecting dust since then. He gave the car to me and I took it for an MOT to see what was wrong with it. Unsurprisingly the brakes were at 50% and uneven but it passed on everything else.

The brake pedal was hard to press but the car did stop, eventually. I suspected the brake cylinders and calipers had seized so changed them.

In changing the back brake cylinders it lost fluid both sides. The brake pedal hit the floor with no resistance from then on until I bled the rear wheels using an Eezibleed. Then the brake pedal firmed up.

I fitted the new front calipers and bled them with the Eezibleed but no fluid flowed on loosening the bleed nipple or even with it removed. Even loosening the bleed nipple after removing the eezibleed and using the brake pedal to try and get flow didn’t work. I did use a Halfords plastic pipe clamp on the flexible pipes so may be the internal part of the pipe has compressed shut?

I’m suspicious the master cylinder maybe the problem although the brake pedal did hit the floor after I changed the brake cylinders but before bleeding them. If the master cylinder was seized I guess that the brake pedal wouldn’t have hit the floor?

I’ve looked at sourcing another master cylinder but it seems out of stock on every site I go to and is £200-300 to replace which is 4 or 5 times the cost of standard types so Id rather be sure about it before committing to buying one.


I’d be grateful for your thoughts.


Thanks

Are you getting any braking effect on the front wheels at all - I mean if you jack it up and turn the wheel by hand with someone pressing the pedal do you get any effect? If nothing seems to be happening then try loosening the front brake line/s at the master cylinder and see if fluid oozes out when you press the pedal - only needs to be by about half a turn of the nut.

After standing for so long the master cylinder has to be suspect I would think.

I don't like clamping brake flex hoses, although I do it when there is no option but only apply a minimum of clamping effort. Instead I prefer to use a plastic sheet over the reservoir, held down with the cap which usually "hydraulics" the system and will stop fluid leaking out at the wheel end. I also have an eezibleed but rarely use it because I find it doesn't actually drive the fluid with much force. I prefer to pump with the pedal BUT put a block of wood under the pedal so it can't travel down any further than it could under normal heavy braking. By doing this you stop any problems that might arise from pushing the piston into an "unused" portion of the cylinder - doing this, ie going to the floor, with an older master cylinder often causes seal damage.

So, if you do get fluid seeping out when the pedal is pressed with the nut loosened at the master cylinder, and bearing in mind that you've previously clamped the flexy hoses, I'd slacken the hose where it goes into the caliper and if no fluid comes out here when you pump the pedal I think the flex hose is a likely culprit? You just have to start at the m/cylinder and work down to wards the wheel - a bit like doing a Hydraulic version of an electrical continuity test?

Easybleed often works better at very low air pressure . Try easy bleed at low pressure and short pedal pushes.


Remove master cylinder , strip it , clean it, check for rust / scoring in bore and on pistons.

On an older car never use the full pedal stroke when bleeding the system in case there is rust in the bore lower down than the pistons normally travel. Any rust / scoring/ damage will damage the seals.

Thank you for the replies. It looks as though my flooring the pedal may have done more harm than good. Bugger. I'll try slackening the brake line tomorrow and see if a light press on the pedal will cause any fluid leakage.

I can't see why the brake cylinders and calipers were seized and the master cylinder wouldn't be but the hydraulic clutch seems okay. Maybe just luck.

I expect I'll end up removing the MC anyway and check it if it fails the above test.

I've tried searching for a repair kit but no luck so it looks like a new one is on the cards. Ouch.

I'll let you know how I get on. Thanks again.

These symptoms sound to me that it is possible its the brake servo not the master cylinder that's up the creek.
New master cylinder is only about £20-£30 google fiat punto 176 master cylinder. (strip, clean and do the test above to make sure lines are clear of any blockages).

However if its the servo that the big cost £80 to £200. check for secondhand parts on this one. Cant recommend any since I live in italy both parts together only run at about 50euro used so I cut out the fault finding and change the lot

Thanks Chris, that could be the case. When I first started the car it blew a lot of smoke out the exhaust. It did this and ran really rough for a while each time I started it but then sometimes it was fine. The petrol pump wasn't making any noise so I got one on eBay and replaced it and it runs really well. However when I restarted it a couple of weeks later it blew another load of smoke out.

So maybe it is the servo or even the vacuum pipe. The revs on start up when the engine is cold are about 1300/1400 and go down to 1200 after a while but the engine didn't have time to warm up sufficiently so I thought this maybe normal?

I put my foot on the brake pedal with the engine running and there was no dip in revs but taking my foot off the pedal the revs rose by 100 rpm or so and then dropped down again. I'll check the vacuum and the hose for leaks.

No luck sourcing a new master cylinder . Even the Lithuanians haven't got them. I have seen a servo for £30 odd quid new so as you say it makes sense to change the lot.

The brake servo should have absolutely no effect on bleeding brake fluid, unless the push rod in the servo connecting the brake pedal to the master cylinder piston has disappeared.

Please post a picture of master cylinder
And does car have abs ?

Thank you. There's no ABS. If it is the master cylinder I can get a scrap one ranging from £35 to £145 but the £35 scrapyard has poor ratings but at least I know I can get one.

Daft question probably but there are two Bosch MCs used on this car but the other one has the outlet ports in the same position but further apart. It's only £40 odd. If the flange and the connecting rod is the same and the pipes move enough would it be an option? I suppose its down to whether the displaced volume of fluid is the same?

Not a daft question but I would say even though the correct master cylinder harder to find and more expensive it will work with the brake system fitted to your car.
It will fit the servo
It will work correctly with what ever load compensation valve is fitted or other valves fitted so they rear brakes don't lock up before the front brakes.

Looking at pic I wonder if it is a stepped bore cylinder that is to say it has two pistons of different diameters .

Can you look at master cylinder to see if front pair of pipes feed rear brakes and rear pair of pipes feed front brakes?

Gefrs said:

Daft question probably but there are two Bosch MCs used on this car but the other one has the outlet ports in the same position but further apart. It's only £40 odd. If the flange and the connecting rod is the same and the pipes move enough would it be an option? I suppose its down to whether the displaced volume of fluid is the same?

Click to expand...

As Jack says, not a daft question at all - but, I'm always very nervous about fitting anything safety related which isn't a standard original fit part. Have an accident and the insurance guys can get very inventive over why they won't pay up!?

Master cylinder part numbers for right hand drive as follows

Bosch part number 0204123524
Fiat part number 9948325

jackwhoo said:

Not a daft question but I would say even though the correct master cylinder harder to find and more expensive it will work with the brake system fitted to your car.
It will fit the servo
It will work correctly with what ever load compensation valve is fitted or other valves fitted so they rear brakes don't lock up before the front brakes.

Looking at pic I wonder if it is a stepped bore cylinder that is to say it has two pistons of different diameters .

Can you look at master cylinder to see if front pair of pipes feed rear brakes and rear pair of pipes feed front brakes?

Click to expand...

I'll have look in the morning and see. From memory the front left (closest to you in the image) goes to the offside front wheel. I think you're right, best go for the correct one especially as its the brakes.

It's interesting about the stepped bore cylinder. That could answer the fact that I can bleed the rear cylinders but not the front calipers. If as you say the cylinder is split in two then one part could be damaged. I don't know the internal mechanics but its sounds feasible.

Using the Eezibleed, though, the MC is not actuated and brake fluid flowed at the back but not the front so I guess it could be collapsed flexible pipes or a detached seal in the MC. I don't suppose I'll know until I take it apart but I'll do as you all advised and loosen the connection to the MC first

Struggling all evening to find a master cylinder new or from a scrappy. What would prevent me from fitting a Punto Mk2 servo, master cylinder and pressure regulator to the Mk1? I suppose the pipework to the wheels being the same configuration is one and the fitting holes through to the brake pedal would be another? Just a thought.

Have you tried giving the lads at Shop4parts a ring: https://www.shop4parts.co.uk/?name=contact They have access to far more than they list on their website and have always been pleasant and keen to help whenever I've rung them. Just a thought.

Strip and clean the one you have see if it is the problem.
It may clean up and be ok.

https://www.eurocarcare.net/contact.html
If you do end up needing one try these people.

I think the MC is going to come out as you suggest. I tried shop4parts but they haven't got one but thanks anyway. In fact thank you all for your time in relying. I'll let you know how I get on.

Gefrs said:

I think the MC is going to come out as you suggest. I tried shop4parts but they haven't got one but thanks anyway. In fact thank you all for your time in relying. I'll let you know how I get on.

Click to expand...

Good luck, my fingers xed it will be ok .

Definately interested in outcome.

You can clean internal brake components in methalated spirits which is less harmful to skin than brake fluid.
brake fluid strips paint very quickly so don't get it on paint.

Jack