Sunday 16th June 2002
Bled the air from the front and rear brakes after refitting the bias pedal box assembly. The pedal feels a lot firmer, and the front brakes are releasing properly now.
Refitted the steering rack with new track rod ends, and I now have a small amount of toe out instead of lots of toe in.
I'm tied up with work and other commitments over the next 10 days, but I'll see what track time I can book at Mallory Park and at Bruntingthorpe.
Changed the Oxygen sensor on the Mondeo yesterday. The Ford diagnostics codes showed that it was faulty, and I bought an equivalent sensor from Halfords and it only took 10 minutes to fit. I'll get the car re-MOT'd in a week or so, when time permits. I've spent over £420 on the Mondeo over the past five weeks, new tyres, exhaust, suspension arms, oxygen sensor, and the time at the Ford dealer to get the fault diagnosed. Considering I've not spent any money on her over the past three years, apart from the usual oil change etc, its not bad value for money. She may be 8 years old, but she still drives and performs like a new car with the bullet proof 1800 Zetec under the bonnet.
Tuesday 11th June 2002
The brake bias box assembly is now back on the car. I've shortened the push rods on both cylinders so that when no force is applied to the brake pedal, the push rods allow the piston in the cylinders to return to the end of the cylinders. This in turn relieves any residual pressure in the cylinders, as fluid is allowed to travel back in to the fluid reservoirs. Previously, I'd discovered that the push rods were about 10mm too long, and the cylinders were not allowing residual pressure to be released.
I've also replaced the rear master cylinder with a 0.75" version, (was 0.7") which will reduce the pressure in the rear circuit, which should prevent the rear disk brakes from locking up before the fronts! I just need to bleed the air out of the system, and I'll be able to see if the setup works properly.
The amount of data downloaded from the zetecinside site has quadrupled over the last couple of days. Over 240 MB of data a day is now being read from my site! Wow. Thats a lot of new visitors, most of whom probably read Performance Ford magazine! A big Hello to all the new visitors, and please make sure you come back regularly to see how the car progresses over the next few weeks, with test/shakedown sessions at Mallory park and Bruntingthorpe about to be booked.
Monday 10rd June 2002
Well, we made the front cover of Performance Ford magazine. And the article inside the magazine is brilliant. Thanks to Keith and Gazza for doing such a good job, though 5 pages don't seem enough for the amount of work that's gone in to the car. Thats what the web site is for I suppose. Click the magazine cover to read the article on my Fiesta from the magazine
Monday 3rd June 2002
I now know whats wrong with the brakes. Having removed the brake bias box assembly, and stripped the mechanism down on the bench, its obvious that there is a design fault. The symptoms are that I can press the brake pedal, and the brakes come on, but they won't release, and the pedal feels awful, it goes solid with no feeling.
The residual pressure in the calipers/pipes/master cylinders is preventing the brake calipers from relaxing, thus the brakes pads are still pressing against the disks (rotors), even though there is no force applied on the brake pedal.
But how can this be? I'll try to explain. The master cylinder push rods are too long for the design of the pedal box. Therefore, the push rod that acts against the piston in the master cylinder, is constantly under compression. With the bias adjuster linkage connected, both the push rods are moved about 1" up inside the master cylinders, and this is preventing the residual pressure built up in the brakes to escape, when the brakes are released. On the bench, when the push rod is allowed to move all the way out of the master cylinder, the piston moves far enough to allow the fluid to travel back in to the reservoir port. Now, the next problem is, how do I fix the fault? I will have to shorten the push rods, sufficiently to allow the pistons to sit at the end of the cylinders when off, and there must still remain enough travel to allow the pistons to produce enough pressure to operate the front and rear brakes.
So that's a big 0/10 for Trans Auto Sport for making such an elemental design flaw! Or in other words, do you ever get the feeling that you're doing the development work for a company when you buy their 'tested' products? I certainly do.
Here's a photo which should illustrate the problem. The steel cylinder, part A should be screwed on to the threaded shaft D, (spin B through 90° when fitted) however, the blue anodised part B cannot screw any further on to the threaded push rod C, because the push rod C hits part A. So if I shorten push rod C, part B will be allowed to move further along the push rod, aligning A with D, so that at rest, with no force applied to the brake pedal, the master cylinder piston will be at its proper resting position, allowing the remaining pressure in the brakes to be released. Thats the theory anyway, and please tell me if you think otherwise. I'll try to get the push rods shortened tomorrow. I'll need to get a die to cut some more thread on the push rods, and as Halfords are open over the bank holiday, in between painting the outside of the house and replacing the roof on the shed (outhouse), I'll see I can get this sorted and everything plumbed back in for testing.
Saturday 1st June 2002
Its the Jubilee weekend here in the UK, so we have two days holiday next week, and then we're back in to work on Wednesday the 5th. Looks like I'll be fixing the Mondeo today. She failed the yearly MOT on emissions at tick over?!?, too much CO apparently. Anyone any clues as to what causes this? I also had to replace the rear tyres with new ones as they'd started to perish due to their age. And I'm currently replacing the front suspension wishbones at the moment, because their rubber mountings had split. I changed the drivers side last night, and today its the turn of the passenger side. However, you can't get one of the bolts out on the passenger side, because the bolts are dropped in from above, and the gearbox is sitting over the bolt, so you can't extract it, without cutting the head off the bolt, and dropping it through the hole. I'll probably have a go at drilling the head off the bolt and chiseling it off.
The web site is now reaching over 600,000 hits a month, which is pretty surprising. I wonder how many extra visitors we'll have after the July Performance Ford magazine article featuring the Fiesta is published on the 6th of June. Make sure you reserve your copy!