A very big high to you all from a newbie from London in the United Kingdom. I run a 2004 F150 Lightning that I use as my daily driver. This is the 2nd Lightning I have owned, previously an 03 year model. My business partner also runs a 2004 Lightning.
The problem is that if you pump the brake pedal whilst the engine is running you can push the brake pedal to the floor. If you push real hard on the pedal she'll go to the floor. Without the engine running the pedal is hard. Now I did not have this problem on the 03 Lightning and my partners truck is fine.
I have replaced the brake master cylinder, the Servo unit and now the brake valve block and it is still the same. You can hear a slight hissing when you pump the brake pedal.
I have spoken to Ford SVT and they reckoned they had never come accross this problem before. There are no SVT dealers in the UK so at the moment I am a little bit screwed. Any help or advice would be greatly appreciated, thanks Graeme

 

i would check your vacuum hose that goes to the brake booster, as well as the booster itself.. sounds to me like you losing vacuum preasure for the power brakes.. hope this helps

 

With the engine running it should be much easier to push and should travel further. Is there a problem stopping? Unless there is a problem stopping, it sounds like the normal function of the brake system. My 00 does this and everything is working as it should. The only time I ever really notice this is when I'm bleeding the brakes and pumping them up. They go to the floor because you are applying more force with your foot than it will ever experience during driving conditions.

 

Welcome to the World Of Lightning Brakes dont work worth a schitt....

graeme73s if SVT told you they never heard this before they are soooooooo full of schitt, there are hundreds (if not thousands) of L's with the identical problem. My 02 had that problem since the day I bought it new off the showroom floor, at any giving time I could push and hit the floor with the Brakes while it was running. And even know you've had one before and it was diff that doesnt mean anything, it seems every single one is a little differant.
For instance my 99 Lightning stops waaaaaaaaaaaaay better than the 02 did,
(but they still suck and the pedal is mush).

As Rich (Hostile said) there are some things you can DO or CHECK.
On my 02 I changed the Vacum Booster Check Valve "Thingy" and it helped A LOT. Later I changed the Master Cylinder and it also helped A LOT, lastly I put Drilled and Slotted Rotors and Hawk pads on it, that also helped A LOT.
After all that I still had some Brake issues though, then I sold it.

My 99 has all factory stock brake parts but it's 100 times better than my 02 ever was ??? You can search this Forum and prob find over enough brake post to last a lilfetime, GOOD LUCK and please do let us know what you find.

 

To follow up on what Rob said, it's not an SVT problem, it's a known problem on 97-03 F150s in general. There are 2,400 posts in the Brakes forum here. Any Ford dealer should be able to help.

We have no SVT parts on our brakes -- they are all rummaged from the standard truck parts bins. As I recall, we have Super Duty front brakes and Expedition rear brakes (but I could be remembering wrong or repeating BS).

 

I need to swap my vacuum check valve....I have about $6,000 worth of big brakes on my truck and the pedal still has a less than comforting feel to it, the brake feel on my girlfriends $16,000 base level VW golf has a better brake actuation system.....hmmmm

 

If I can help you out let me know.

I would do a complete bleed of the system and install some new fluid all the way through just to eliminate any air or bad fluid and see if that improves things.

Like Rob and Tim have said there is a wealth of information to be gained from this forum and some usefull advise too.


There are a number of good suppliers of brake upgrade components who ship over from the US weekly and I have some contact numbers.

I am located Just a short burst up the M3 from London and do many meets in the London area including regular trips to Avonpark and Santapod.

Ricki RFMPipeline@aol.com

 

One of my friends has a lightning (I wish I did)--he told me of the same problem he had...and he says that replacing his brake lines with stainless brake lines helped exponentially. He claimed it was definately worth the weight to be able to have the confidence that after going fast, he could stop...

Good luck

 

Thanks guys for your advice but it seems somewhat depressing. It sounds like whatever I do I am not going to solve the problem. Ford UK would be a total waste of time as these vehicles are not officially sold in the UK. I'm real pissed with the mechanics I use as the parts alone have cost me around £1100 and the brakes are no different. The brakes have been blead thoroughly a number of times. The check valve is an interesting thought but why should you get a rock solid pedal when the engine is off and a spongy pedal with the engine running. It must be a solveable problem. If I had to carry out an emergency stop from reasonable speed the pedal would be on the floor. Luckily enough I don't ever tow with the truck but if I did I think I'd be in real trouble.
Being totally honest I do have other toys to play with but as a day to day tool personally there is nothing better than the lightning. I could sell it and buy another 2nd hand lightning but I could not bring myself to lumber someone else with the problem. I only bought the 04 as my 03 had done 60,000 miles and I thought as it was last of the line I'd start again fresh. Any other thoughts would be greatly be appreciated and in the mean time I'll do my upmost to solve the problem. There's got to be a simple solution. cheers and thanks Graeme. I'll keep you posted

 

Wow--good man. I still say that stainless brake lines (though expensive) are a great way to go. They're raved about in the brakes section. Aside from that--read into the brakes section of the site. They're sure to have the answer (I'd repost if I was you, except under the Brakes category)

Good Luck (If you don't want the lightning--I'll take it. Just pay shipping and it's off your hands...)