Brake snag post garage work

[Fordhom]

Hi all, hoping for some pointers on a possible snag with my Chim 4.5.

Had her in the garage last week for some bits and pieces, and as the brake lines were looking tired, had them replaced with braided metal jobs, vain bugger as I am. In the process of so replacing, apparently they were unable to bleed the system properly, diagnosed duff seals on the master cylinder, so changed that too.

Collected the car today, and wasn't too happy initially with the brakes - pedal seemed to travel a long way before they took effect, seemed a lot spongier than before. Turned round, drove back to garage, and asked for opinion of the guys there, who have my total trust - used them several times before, and have always been highly knowledgeable and trustworthy. They tried the feel of the pedal statically, and then on a test drive, and assured me it felt fine. I then drove home, more confident in operation of the brakes, and indeed seemed fine, although I still felt there was a fair bit of travel in the pedal before they became effective.

Left car cooling down while I was at work, then on the drive home the brake response seemed very poor again - tried putting my foot flat on the floor while doing about 5mph, pretty sure it did actually hit the stop. Car did decelerate, but not the instantaneous stop I'd expect previously from such an action at that speed.

With the engine off the pedal feels firm, like before, but when the engine's started from cold the pedal suddenly goes very very spongy, with poor response.

Any ideas on what I'm dealing with? Would an airlock display the different symptoms engine-off/engine-on and apparent increase in brake performance after driving for a while that I described? Sorry if I'm being a bit basic, have to admit my technical knowledge is poor at best. I need to call the garage tomorrow anyway, so would be grateful if anyone has any suggestions! Annoyingly, as I move around a bit with work but want to use a garage I trust, I'm currently about four hours away from the garage, else I'd definately take the car straight back.

Thanks in advance for your help Gents.

[steve-v8s]

You don’t say but did you have new pads as well ? if so they may simply need bedding in before they work. Other than that it sounds like you still have some air in the system.

[chimalsu]

if you put your foot on the brake pedal and start the engine the pedal will go soft because once the servo kicks in you need less effort to brake.if the piston seals have been replaced the calipers will have been taken off and put back if you have had new pads they need to bed in and if they put back the old ones back they may not be sitting in the same place so they to will heve to bed in,give it a while maybe up to 100 mile if no better then go back

[spend]

The pedal should still 'bite' when the servo kicks in. Get them bled again as a first step I would suggest + new fluid if you didnt have it changed, and check for leaks.

Dave

[Fordhom]

Thanks for the swift replies chaps.

No new pads, at least not that I requested or was charged for! Presume fluid was changed with the lines though.

Up for bleeding the brakes as a first stab, think I still have a one-way bleeding tool thing from some clutch dramas with my old S3. Forgive my gross ignorance, but, not having bled brakes before, what order should I bleed them in? And how the hell do I get to the master cylinder to do so?

For the record, as the engine starts and the servo kicks in, the pedal really does go VERY soft.

[mdotrutherford]

Most definately air still in the system, check out a Gunson Eezi - Bleed kit from Halfords under a score IIRC
comes with a secondary reservoir pressurised by spare tyre pressure to keep a head of fluid, just requires
you to go around each wheel opening the bleed nipple until all the air is out. Best theory is O/S/F-N/S/F
-O/S/R and lastely N/S/R, just keep a eye on the fluid level each time, and access only required to top of
master cylinder. Comes complete with all the gubbins and instructions.
Brgds
Ian

[Fordhom]

Ian - thanks, will probably get myself to halfords tomorrow. Where can I actually get access to the master cylinder? Have had a poke about and can't seem to find a way to get to the bloody thing!

[mdotrutherford]

The brake master cylinder is the white one with wires attached to cap O/S wing - got Ford on it !
Dont confuse with the clutch one under the blister cover.

[hut49]

Others have pointed to the likelihood that there's air in the system somewhere that should be resolvable with careful bleeding (I'd also replace the fluid too, if I was going to take over the job). But I'm still not sure why you have accepted that there's a problem youneed to fix, rather than the garage. The consensus (though none of us has driven the vehicle, of course) is that there's a fault following their work. Shouldn't they fix it?

[GreenV8S]

I would guess you have an air lock in the braking system. You might struggle to clear it just with conventional brake bleeding techniques (which basically just flush the fluid through), if the system has been drained and now has an air lock you will need to dislodge it. If you can figure out where it is (or might be) then tipping the offending component up to let the air out of the top as you bleed it will be your best bet.

[Fordhom]

hut - Sadly the garage is about 4 hours away, so if I can resolve the problem easily myself then that's what I'd rather do than drive back! Like I said, when I expressed some concern they took the car for a test drive, and all seemed well then, as indeed it did immediately after that - although not as responsive as I remember the brakes being before I had the work done. And, once again for the record, the garage in question have always in the past been extremely good - would recommend them to all without hesitation, although guessing I'd best not mention the name here for fear of being thrown off for advertising!