Series 3 Brake Pedal / Master Cylinder adjustment - PLEASE HELP!

Hello everyone - I'm new to this site but have come in search of help!
I have a series 3 109 (1981) and can usually get the work done that it needs fine, but I'm struggling with something I think is so basic as to be embarrassing and am hoping someone here can help.
Basically - I can't figure out how to adjust the brake pedal height. Mine is way out (should be 6.25 from the floor and mine's about 5!). The trouble is I can't work out how to access the stop bolts. I have the manual and the Haynes book but am still none the wiser. In the engine bay my master cylinder (attached to servo) appears to all be covered up (see photo). - tried removing the 'hatch' at the top to see if i could locate any nuts but no joy.
I'm sure I'm being stupid, but i've looked all over the web to find a description of how you actually get access to adjust the brake height and can't find anything - can anyone help describe to me how i actually make the adjustment??
Would be very much appreciated!!! Thanks

The master cylinder is mounted on the front of the servo, under the reservoir but the linkage adjustor nut should be accessible through the round plastic bungs in the side of the box.

Thanks for the reply - but all i can see through the bung holes is a split pin bolt end on one side and the round bolt head on the other. Nothing that I can adjust to raise the pedal height. Do you think I need to completely remove the pedal box (and so also the server and mc) to get to the pedal adjustment? Hoping not as that would be a big ole job and then mean i'd need to rebelled all the brakes (never fun!)

Pedal height is not adjustable if you have servo type pedal box.

Are the return springs fitted and working?
There is some adjustment on master cylinder side of servo.
Is the servo working I think the test is to press brakes on then start engine pedal should then travel further from memory.

Citizen Kane said:

Pedal height is not adjustable if you have servo type pedal box.

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Ah! That’ll be why I can’t find anything to adjust then - thanks!!

Blackburn said:

Are the return springs fitted and working?
There is some adjustment on master cylinder side of servo.
Is the servo working I think the test is to press brakes on then start engine pedal should then travel further from memory.

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Great thanks- will do that test tomorrow. The return springs are in place and doing their job properly.

Is it bent?

The brake pedal is quite a bit lower than the clutch pedal. Might be easier to lower the floor than adjust the brake pedal height!

Has it always been like that?, is the servo a later addition?

As long as the brakes work before the pedal hits the floor, why worry, it's a series, it's like having a wayward child.

Col

Colthebrummie said:

As long as the brakes work before the pedal hits the floor, why worry, it's a series, it's like having a wayward child.

Col

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Cheers for all the replies so far - the pedal isn't bent, and the servo has been on the brakes i think forever, but certainly since i've had it (7 yrs). Brakes do work before hitting the floor, but just think they could be better. Am trying to diagnose what might improve them and spotted that the pedal was much lower than the manual said, so thought fixing that would be a good start. But seems from Citizen Cane's reply that it can't be adjusted so looks like that's not the issue! The servo test Blackburn mentioned I think worked - at least the pedal did travel a little further after the start of the engine, but not by much so not sure if it's working perfectly or not. Will keep tinkering - have adjust the shoes, replaced the wheel cylinders and bled the pipes best I can. There may be some small residual air in the system I guess so I might have to try bleeding again while parked on a slope, or it might be that my m/c or servo has a leaking gasket or something. Thankfully no sign of any leaking brake fluid anywhere (and level stays where it is in the reservoir), just that sometimes when i brake it feels like the resistance stops and I need to lift the foot off the brake and then re-brake to get it to stop. Either that or stamp on the damn thing til my foot nearly goes through the floor. They've never been great since I've had it - but feels like might be getting worse. They do stop the thing though so maybe that's all i should hope for! Thanks again to all for the help.

Speding time on the ajusters could make a differnce, its a fiddley job and easy to overtighten one and overheat a brake. I always carry the tools if I've adjusted the brakes and check the drum temps after a few miles. When you adjust the shoes tighten hard, back off, then try them and hit the wheel a few times with a mallet too and press the brakes hard.

Worth taking the master cylinder of if enough slack on pipes to see if the piston is coming back fully if partially siezed would that cause your sympton . Will measure my servo pedal height next time I get the landrover out possibly thursday , just put it back in the lockup tonight.

Measurement pedal to bare alloy floor from my servo brake 5.5"

Excellent - thanks - that's about the same as mine so looks like all's well with the pedal height. Servo seems to work ok too (far as I can tell - pedal moves on engine start up and there's definitely decent suction leading to it). Took Rob1miles' advice and played around more with the adjusters and after a bit of tinkering think I have made an improvement. Will need to wait til i've given it a few decent miles tho to see if it's really better. If not will look to get a pressure bleeder and have another go at bleeding the system. If still no improvement will bit the bullet and disconnect to have a proper look at the MC (not enough slack to remove without taking off pipes). Am hoping to avoid though as getting the air out is such a pain (plus something is bound to break getting the MC off meaning a rush to buy more spares!).
Thanks to all for the help - most appreciated.

TS2304 said:

Excellent - thanks - that's about the same as mine so looks like all's well with the pedal height. Servo seems to work ok too (far as I can tell - pedal moves on engine start up and there's definitely decent suction leading to it). Took Rob1miles' advice and played around more with the adjusters and after a bit of tinkering think I have made an improvement. Will need to wait til i've given it a few decent miles tho to see if it's really better. If not will look to get a pressure bleeder and have another go at bleeding the system. If still no improvement will bit the bullet and disconnect to have a proper look at the MC (not enough slack to remove without taking off pipes). Am hoping to avoid though as getting the air out is such a pain (plus something is bound to break getting the MC off meaning a rush to buy more spares!).
Thanks to all for the help - most appreciated.

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Pressure bleeder is the way to go

If it’s diesel check the butterfly valve in inlet manifold is closed at idle and hand throttle fully off , this can affect servo performance through reduced vacuum

If the pedal feels a bit spongy, there is probably some air still in the system. Getting the last bit out is a pain. Try using a length of wood to hold the pedal hard down, wedge the wood under the steering wheel and leave it overnight. That can often force the air out.

Col

Hd1966 said:

Pressure bleeder is the way to go

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Can you recommend a decent one that doesn't cost the earth?