Hi all, Sorry I don't get back here much but still working 70-80 hrs a week and trying to have a life on the side.My brake pedal goes almost to the floor either under light or heavy braking conditions. Some history, master cylinder replaced by previous owner as he was also concerned. When I got the vehicle I decided the front discs needed skiming so I had them done and also adjusted rear drums. No noticable difference. Also hand brake never been particularly useful not that I use it. The truck is actually a 93 f 250 extra cab with around 220,000 km (137,00mi). 7.3 idi e40d no oversize tyres or diff changes as far as I know. I think I'm getting appropriate vuccum as everything else I check works. If I get on the brakes hard the big girl pulls up alright and I can feel the ABS working back on the pedal. Is just that I feel it should have more feel. The guy that skimmed the discs suggested that perhaps the master cylinder had been replaced with an incorrect unit. Did the 93 also come out with drum front as this my make a difference? Any advice would be much appreciated.
Cheers, Frank- Bedfordale Western Australia.

 

You might try adjusting the rear brakes some more. Read a post yesterday on oilburners, guy had everything brake related replaced except the hard lines and still had a low pedal. The shop had a second mechanic finally take a look and he just adjusted the rear a bit more and fixed the problem.

 

What he said but it also sounds like there is air in the system and the fronts were always discs.

 

+1 on air in the lines. Bleed the brake lines. It's a cheap fix that doesn't take too much time.

 

Also possible the brake drums are getting to the max wear limit.

 

I thought about air in the lines although it seems strange after the master was changed it would still have air in the system. Also is there a wear indicator on the drums or do you just measure them if so how big is to big. When I adjusted the rears last time I took them until the shoes were just starting to touch, should I go further than this.

 

Sounds like you are not far away on the brake adjustment.
As for air in the system if the person who fitted the new master cylinder did not bench bleed it before fitting, the system could be full of air. So try bleeding the brakes. Bleed the right rear, left rear, RABS valve module, right front then left front.

 

Does that bleed order change at all for the fact that the truck is now a right hand drive and as such has a right hand mounted master cylinder?

 

Not really just remember the RABs valve between rear and fronts........ That valve is usually on the left side frame rail under the (USA) driver seat........ is yours still there.

The drums have a maximum internal size, usually printed on the outer rim of the drum... this is one place where size matters....... too big bad brakes.

Your braking effect is it continually smooth ........or do you start off ok then it jams on and your face hits the steering wheel.......that indicates a possible booster problem.

How is your vacuum pump operating.......low vacuum can also cause a problem.

 

PLC7.3, Brakes are smooth all the way even in extreme stopping conditions except for the operation of the abs which also feel fine. The pedal just seems to go to far. As far as the rabs unit I haven't looked for it but I would say it's in the original place as they only move the bare minimum in these austrailian conversions to get around licencing. Vacuum pump appears to be ok as it would be more likley to cause hard brakes if it was failing I would have thought. As for the drums I will look at them as soon as I can but I hate to think what they are worth to replace over here. Things can get a bit pricey around here. A few examples, starter motor $900.00au, 7.3 short motor ex USA $15000.00au, Current market value for my 93 7.3 factory turbo extra cab with aluminium tray back $35000.00au. No such thing as a local junk yard for clunckers or parts over here with imports. Either all new or special order. Will just have to see what I can dig up. Still it is the best truck I have owned out of the few asian and european trucks as far comfort and it tows my 2000kg trailer for my construction work like a dream. Last month 2 ton trailer plus 1 ton of timber on top with another 2 ton on the truck sat on 120 km/h all the way to a job 300 km out of town like a dream. Got out feeling good and ready to work not like my last cab over could hardly walk after 1hr in that.