Front brakes not releasing

[Alec]

Hello Forkie,

what I am looking at is the push rod in the servo which, when the brake pedal is depressed pushes the piston in the master cylinder. At rest there should be a small clearance between servo actuator rod and the master cylinder piston. If the actuator rod is too far out then the master cylinder piston does not retract to it's resting position and may block the port back to the reservoir and so have some pressure remaining in the system, when there should be none.
This would affect all the brakes however, not just the front.

Alec

[johnnydog]

You can move the master cylinder away from the servo without disconnecting the brake pipe sufficiently to see the push rod. The brake pipe is reasonably flexible due its length to the bulkhead, and there is enough 'free' movement to ease it away from the servo without putting any undue strain on it. The push rod free length can easily be adjusted if necessary.

[Forkie]

Hi guys -- yes thats understood, and is actually something that has NOT been checked....i have been on the phone for an hour to this chap im hoping to get the spare parts from, and he is also a bit stumped - but has also suggested this check. I removed the servo with MC many years ago as the seals were gone etc. Could i have re-fitted them incorrectly or not noticed the rod length had altered who knows. But definately my next move this weekend.
I assume then the rod must be on a thread, so simply turn it.....it was 15 odd years ago so cannot really remember the set up now .

[Forkie]

So.....ive been thinking about the last few posts ( and all the others) for a long time this evening. The above posts , moreso my last, still stands , in that i will try to check that setting. But my memory has been working overtime this evening. Not sure if this is relevant or not, but here it is:
When i took this off the road in 2008, after realising all the running gear was shot, part of that was to replace the M/C seals. I decided to remove the M/C, and servo ( servo mainly to freshen up the finish on it). That led to obviously disconecting the servo inboard -drive side parcel shelf out, brake light switch etc to get to the bolts to said servo. Once fitted back in, whenever the ignition was on/ engine running, the brake lights were on all the time.... thought not much of it at the time - least of my concerns, maybe just a dodgy switch.
Fast forward to early 2022, when it got shipped to my garage guy, i mentioned in the huge list of jobs to do that the brake lights were always on.....during his work updates he mentioned he had sorted the ' brake lights always on ' issue - he said that ' the bracket was bent,so i straightened it'. Never thought much of it then other than how strange.. But now, i am thinking ' what bracket, how was it bent, and is there a link there? As far as i can recall, the brake light switch is an all plastic affair, and i would of been really careful. I am not a bull in a china shop kind of guy. Does this indicate anything to you?

[Forkie]

In short - when i brought the car, the brake lights were not on all the time with ignition on or engine running ! But when i started stripping and changing bits,i.e. the M/C , Servo and brake light switch, and refitting, that put the brake lights on everytime the ignition was engaged - engine running or not. So i am now thinking this is a me cock up - what have i done wrong?

[Alec]

Hello Forkie,

unlike most cars of that era the 2000 had pedal actuated brake light switch fitted to a flimsy bracket such that the switch contacted the pedal. If the switch does not touch the pedal when at rest then the brake lights will be on. Either the bracket got disturbed and bent or the pedal is not returning to the original position, the former being more likely.

Alec

[johnnydog]

Hi Nige,
As Alec says - any problem due to BOTH brake lights either staying on or not working at all, is often due to a faulty switch, or the plunger on the switch not being depressed sufficiently (brake lights staying on) due to its mounting bracket being incorrectly positioned. The bracket is welded to the pedal box and can be easily disturbed during any work in that area resulting in issues with the brake lights (operating or not).
The switch plunger only sits gently against the top of the upper part of the pedal, and requires very minimal effort to activate it (and the brake lights).
There also should be a stout spring clipped in a hole in the top lip of the pedal box; the flared end hooks into a hole on the side of the brake pedal. This ensures the pedal returns to its upper most position, and allows a small degree of free play in the pedal, before the hydraulic action can be felt. If you put your foot under the brake pedal and try lifting it and you have about 1/2" of free play, then it's likely this spring is broken.
Neither of these two aspects however should have any bearing on your brakes binding after bleeding (unfortunately!).

[wild bill]

Okay,having followed this problem from the beginning of time!,here's a check for you. Jack up the car, remove both front wheels and apply footbrake a couple of times to allow the wheels to "drag. Now take a hammer and clout the calliper on the "lump" in the casting where the piston is. Does the wheel now rotate freely? Yes?, then the problem is in your callipers. It may be worthwhile removing them, removing seals and cleaning out the "grooves" that the seals sit in. Clean out, polish piston and refit with clean brake fluid to lubricate. I've just had this problem with one of my bikes' Honda CB 750 with twin front discs.This has only done 13500 miles, and there was no wear on anything, the problem was just from lack of use, which ties up with your Triumph. Got to be worth a shot,5 minutes takes the wheels off, couple of quick hits may put you on the right bus.
Good luck,Bill.

[Forkie]

Ok so maybe the bent bracket that the brake switch sits in DID get knocked, which if you guys reckon is easily done, i will accept that then - even though im not quite sure how - like i mentioned yesterday i'm not a ' bull in a china shop' kind of person. Anyhow that got sorted a couple years ago - as i only recalled it last night, just thought i would mention it.
Bill - the recon calipers have since been stripped,again, as i am fairly sure have been mentioned in this 'Doctor Who' time span of a post, to find nothing wrong, re - sealed, again, all was good, clean and shiny, but if needs be i will take the 'clout it with a big hammer' approach if all else fails
John - so whipped out there just now to feel pedal movement. So got a little movement downwards - i think i put a few days ago - a 3/4 " free play, then hit slight resistance - then a further similar distance down - then solid ( engine not running).
PULLING UP with my hand under the brake pedal - solid- no movement whatsoever.
So regarding the 'too long a pushrod' theory - was thinking today - if that IS the scenario - am i right in thinking when i slacken off the nuts - M/C to servo - as i slacken them off, the M/C moving away from the servo SHOULD then release the pads - as i have in effect pulled the piston away from the pushrod....

[Forkie]

I am convinced now i did something 'wrong' 16 odd years ago. I cannot have the only 2000 in the world with this issue, that none of you guys can sus out, nothing is obviously wrong. It is a relatively basic car with a basic braking system. Something glaringly obvious is amiss somewhere.