brake servo freeplay...`

[qwakers]

on my discovery 1 I've had a issue with the brakes for a very long time. but as i haven't driven it for a year that's not so bad lol.

anyway, sometime late in 2014 i broke a brake pipe, dumping all the fluid. and this is where my problems began, i replaced all corroded pipes and bled it it but i couldn't get a pedal, no matter how hard i tried. so i decided i must have damaged the master running with no fluid, so i bought a refurb kit and refurbished it. this was fine for about a hour but then the seals failed again.

rather than rebuild it again i just replaced the master with a Lucas part. the brakes now worked but with a very long travel and you couldn't get them to lock. this was the state of play September 2015... (id been doing my house up so hadn't driven it )

after much pondering and reading i decided that as id replaced everything else it must be the servo push-rod free-play. I've never adjusted this and looking online i couldn't find a good write-up on how to adjust it so i got my thinking cap on and came up with my solution.

first off this can be done with the brake pipes attached but it is far from recommended. they will stress fracture very easily so i undid them all first.

then i took the master off, this reveals the push-rod and its adjuster. then i took a piece of plastigauge and attached it to the end of the rod. (do NOT squash it lol)

i then put the master back on and pushed it home, then removed it again. as expected the plastigauge had not deformed at all, i then pulled the push-rod out and using a pair of pliers to hold it i undid the threaded part 2 turns. to refit the push-rod i put a breaker bar between the brake pedal and the seat to hold the brakes on and used a long-reach socket to push the push-rod and its retaining clip back in. i then removed the bar from the brake pedal and refitted the master. id gone a bit too far and deformed the plastigauge so the push-rod must have had no Clearance to speak of. i repeated the process until there was JUST a dimple in the plastigauge to show the rod was nearly touching the master, this leaves clearance so the brakes don't lock on when everything gets hot.

refitting is the reverse of removal as they say in the book of lies, and once bled up i drove it down the lanes and nearly ended up through the windscreen. the brakes have NEVER been that good...... must be all the new hoses, calipers, discs and pads I've fitted to try and fix what turned out to be a 20min adjustment.

so those of you who say their brakes have always been carp no matter what they do.... try this. it works.

[western]

I did a similar adjustment on my 110 a while ago after converting the rear drum to disc, after a drive the new calipers would be almost fully on so I could hardly move, where you used a plastigauge I used blutac, got the result of a bit of clearance, set it at 1.7mm but over the last gew weeks, thinking that's a bit to much.

[qwakers]

i used plastigauge because i had some kicking around

(after rebuilding a yamaha r1 engine, putting a high lift cam and porting and polishing it whilst i was at it, god that was quick 175rw bhp but thats another story lol)

but yeah anything that will tell you what gap is left will work.

[Mo Murphy]

Now that IS an interesting post qwakers.

Mo

[Snagger]

I had similar issues with a new servo on my 109 - the manuals all state they are factory adjusted and must not be tampered with, but that is wrong - they may have been set with care originally, but nowdays they can be well off.

[ejparrott]

That kind of makes me wonder if that's where some of the problem is with The 109. I daren't touch it though...took ages to get any kind of brakes on her, so I don't want to fiddle with them!

[Troll Hunter]

"Factory set" and "lubricated for life" are two of the biggest lies of the auto industry. Don't trust either of them, and always go back to the instruction manual, if available, for adjusting settings yourself. As for the "lubricated for life" items, they're a bit more difficult, because they usually don't have any means of owner lubrication. Avoid them if you can.

Mike

[Sheffield]

Lubricated for life means the life of the lubricant. Once that is done the bearing will follow very shortly. Suitable for the throw away qucik profit society in which we appear to live, but poor engineering.

[qwakers]

a good example of lubricated for life is the pk6 gearbox fitted to the renault laguna 2. it is almost entirely the reason the laguna got a poor reputation for reliability. its possible to change the oil though and i do it every 50000 or 5 years. dads car ( i bought it new and passed it on to him a few years ago) has now done 190000 and its perfect, 99% of cars have eaten there gearbox before 100k.....

then theres the stupidly long service interval that kills the turbos, i always do the oil change yearly or 10k, whichever is sooner, again the turbo is still perfect. go figure...