Long brake pedal travel

the_wolf · Wednesday at 08:53

Twice now my Defender has failed its MOT and subsequent retest due to the brake pedal having too much travel. The tester said that he knows the brakes are there and they work but the pedal has got too much travel and is nearing the floor when pressure is kept on it. Unfortunately it's a fail. The push rod is at the ideal length as far as I can tell and the brakes have been bled multiple times with zero air in the system. I'm not losing any fluid, all brake pipes and flexis are new (flexis have also been replaced with the steel braided type), the master cylinder is new and the servo is only a year old. Rear pads are new as is one caliper with the other being only two or so years old. What else can I do to try and sort this as it's doing my head in.

Defender 110 300tdi

miktdish · Wednesday at 11:03

There is adjustment on the rod as it enters the master cylinder in the brake pedal tower.

Here is a link to another forum with more info that may help ..

Brakes - long pedal

Ive not been 100% happy with the braking on the 110 for a while. OK, so Im probably comparing a 2.5 ton 110 with an almost-empty 90, but I do feel like it ought to stop better... and the pedal is low and I cant seem to get it any higher... A while ago I fitted new ventilated disks plus...

www.lrukforums.com

the_wolf · Wednesday at 12:45

miktdish said:
There is adjustment on the rod as it enters the master cylinder in the brake pedal tower.

Here is a link to another forum with more info that may help ..

Brakes - long pedal

Ive not been 100% happy with the braking on the 110 for a while. OK, so Im probably comparing a 2.5 ton 110 with an almost-empty 90, but I do feel like it ought to stop better... and the pedal is low and I cant seem to get it any higher... A while ago I fitted new ventilated disks plus...

www.lrukforums.com

I had already adjusted the push rod and I'm wary of adjusting it too much and putting constant pressure on the piston itself. The actual brake pedal has about 15mm or so of free play before it actuates the pushrod so I'm happy with that but obviously the pushrod into the master cylinder is the only other real adjustment on it. At the moment the pushrod is sitting pretty much dead on the face inside of the piston and I can feel it pushing the piston inside the master cylinder once that free play on the pedal is taken up. Why it will continue to go to the floor I don't know. Only other thing I can think of to adjust this itself is to lengthen it more, see if that helps and then work back from there.

Def90man · Wednesday at 13:34

I had something similar with one of mine years ago. Eventually it was traced to a cheap servo that was actually flexing when the pedal was pushed, so the brakes were always vague. A new quality servo fixed the problem

the_wolf · Wednesday at 17:21

Def90man said:
I had something similar with one of mine years ago. Eventually it was traced to a cheap servo that was actually flexing when the pedal was pushed, so the brakes were always vague. A new quality servo fixed the problem

Funny you should say that I noticed mine doing that very thing last night. I pressed the brake pedal with a pole whilst feeling the master cylinder so I could tell when the piston was actually engaged and I could physically see the face of the servo flexing out. I've bought a better quality one so fingers crossed it sorts it when it comes in

the_wolf · 2025-09-06T15:21:39+0100

New brake servo fitted and whilst this one definitely doesn't have any flex when the pedal is being pressed I still feel like the MOT tester wil say it's got too much travel. I know that these arent adjustable behind the pushrod within the servo so it's not that. I don't know what else to do to try and improve this? As far as I'm concerned the brakes are spot on so I don't know what he's looking for. Yes if you keep constant pressure on the pedal with the engine running it does go down as you would expect but it's still a decent distance from the floor as far as I'm concerned. I'll post a video

the_wolf · 2025-09-06T15:23:31+0100

meego · 2025-09-06T18:22:48+0100

the_wolf said:
New brake servo fitted and whilst this one definitely doesn't have any flex when the pedal is being pressed I still feel like the MOT tester wil say it's got too much travel. I know that these arent adjustable behind the pushrod within the servo so it's not that. I don't know what else to do to try and improve this? As far as I'm concerned the brakes are spot on so I don't know what he's looking for. Yes if you keep constant pressure on the pedal with the engine running it does go down as you would expect but it's still a decent distance from the floor as far as I'm concerned. I'll post a video

It does look like it’s got a fair bit of travel before you’re getting any resistance to be fair. It’s hard to tell though from a video.

the_wolf · 2025-09-06T18:24:17+0100

meego said:
It does look like it’s got a fair bit of travel before you’re getting any resistance to be fair. It’s hard to tell though from a video.

I know, it wasn't that clear from any video I took. There is only about 15mm free play at the top of the pedal before it starts to act on the brakes though

meego · 2025-09-06T19:13:58+0100

If you’re about tomorrow I can take a run over and we can both have a look at it ??

the_wolf · 2025-09-06T20:30:22+0100

meego said:
If you’re about tomorrow I can take a run over and we can both have a look at it ??

So I've did a bit of digging and what I've discovered is that the bore size may not be correct. The standard master cylinder bore is 25mm but apparently some aftermarket ones have a smaller bore that gives exactly the symptoms I've got. Good brakes but longer pedal travel

the_wolf · 2025-09-06T21:07:12+0100

Found my old master cylinder and re-fitted it and pedals exactly the same so it's definitely not that. I don't know what else to rule out

lynall · 2025-09-06T21:14:33+0100

Bit of a pita, but jack up and remove each wheel in turn and see how much free play the brake pads have.
Seen it first hand where the caliper pistons do not fully return as the wiper seals are dry and when you release the pedal the piston moves back in a millimetre or so, so next press of the pedal you have to take up that freeplay before the pads make contact with the disc.
I carefully lifted up the gaiter enough for a syringe to inject a small amount of brake fluid to act as lube, calipers still okay to this day.

the_wolf · 2025-09-06T22:15:33+0100

lynall said:
Bit of a pita, but jack up and remove each wheel in turn and see how much free play the brake pads have.
Seen it first hand where the caliper pistons do not fully return as the wiper seals are dry and when you release the pedal the piston moves back in a millimetre or so, so next press of the pedal you have to take up that freeplay before the pads make contact with the disc.
I carefully lifted up the gaiter enough for a syringe to inject a small amount of brake fluid to act as lube, calipers still okay to this day.

I could understand if the pedal lost the travel it's got after a couple of pumps once the pistons have moved out to contact the pad but it doesn't, the pedal travel is pretty consistently the same no matter what

jamesmartin · 2025-09-06T22:23:24+0100

the_wolf said:
I could understand if the pedal lost the travel it's got after a couple of pumps once the pistons have moved out to contact the pad but it doesn't, the pedal travel is pretty consistently the same no matter what

often new pattern calipers retract too far instead of just releasing pressure meaning too much pedal travel next time

the_wolf · 2025-09-06T22:30:43+0100

jamesmartin said:
often new pattern calipers retract too far instead of just releasing pressure meaning too much pedal travel next time

Nice to see you about, I thought you'd gone. Is there any way to remedy this if that is indeed the problem?

jamesmartin · 2025-09-06T22:35:15+0100

the_wolf said:
Twice now my Defender has failed its MOT and subsequent retest due to the brake pedal having too much travel. The tester said that he knows the brakes are there and they work but the pedal has got too much travel and is nearing the floor when pressure is kept on it. Unfortunately it's a fail. The push rod is at the ideal length as far as I can tell and the brakes have been bled multiple times with zero air in the system. I'm not losing any fluid, all brake pipes and flexis are new (flexis have also been replaced with the steel braided type), the master cylinder is new and the servo is only a year old. Rear pads are new as is one caliper with the other being only two or so years old. What else can I do to try and sort this as it's doing my head in.

Defender 110 300tdi

how do you know push rod is ideal lenght,too long brakes apply themselves after a short run,too long too much travel on pedal you nwant it just before it starts to apply

jamesmartin · 2025-09-06T22:38:22+0100

the_wolf said:
Nice to see you about, I thought you'd gone. Is there any way to remedy this if that is indeed the problem?

just read tge thread and lynall described a solution,you can clamp the flexis in turn and see what difference there is

the_wolf · 2025-09-06T22:39:33+0100

jamesmartin said:
how do you know push rod is ideal lenght,too long brakes apply themselves after a short run,too long too much travel on pedal you nwant it just before it starts to apply

I've spent ages trying different lengths, i know what happens if it's too long and did fall into this trap before. I put a smear of blue hylomar on the end and basically adjusted it until I was only just getting a little on the piston face. That's the best I could do. As I said brakes are there and are actually good but it's the pedal travel the mot tester has an issue with. I've now replaced servo, master cylinder, all brake pipes, flexis, fluid and bled multiple times. There's enough space with the pedal as far down as it'll go for me to fit the toe of my boot under easily so I don't know what his issue is.

the_wolf · 2025-09-06T22:41:03+0100

jamesmartin said:
just read tge thread and lynall described a solution,you can clamp the flexis in turn and see what difference there is

It's steel braided flexis I've got on

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