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300TDi CSW Phil



Member Since: 03 Apr 2016
Location: Bracknell
Posts: 746

United Kingdom 1995 Defender 110 300 Tdi CSW Epsom Green
New TRW Brake servo on 300tdi
I'm hoping that I'm paranoid but here goes.

I have owned my defender for 6 years and have watched the servo unit deteriorate around the master cylinder fittings for most of that period wondering when to change it.

The time has come, and I have with a new TRW unit which looks identical to the old one (but new and not cracked).

My issue is that I now have a muffled sort of popping sound coming from the region of the brake servo which can be heard in the drivers seat (with the radio off).

Is this normal or have I done something wrong?

The brakes are working better than they ever have. 1995 300 Tdi Epsom Green - It's a keeper.
Wide Track Sankey- In bits- Gone to a new home
M0XQS
Post #731872 29th Sep 2018 4:58pm
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donmacn



Member Since: 07 Nov 2017
Location: Nth Scotland
Posts: 1829

Hi Phil, I'm afraid I can't help too much just yet, but if things go well tomorrow fitting a new steering pump and pipes, then I might treat the car to the new TRW servo that's waiting to go on.

Is the popping noise constant, or just during braking? Donald

1994 Defender 300Tdi 110 SW - owned since 2002 - 230k miles and going strong
(The 'rolling restoration' or tinkering thread: http://www.defender2.net/forum/topic58538.html )
2000 Range Rover P38 4.0L V8

in the past..
RR classic - fitted with 200Tdi
1984 RR classic - V8 with ZF auto box
1993 Discovery 300Tdi

not to mention the minis and the Type 2 VW camper...
Post #731882 29th Sep 2018 6:26pm
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300TDi CSW Phil



Member Since: 03 Apr 2016
Location: Bracknell
Posts: 746

United Kingdom 1995 Defender 110 300 Tdi CSW Epsom Green
Its constant and varies with engine speed, then disappears when brakes are applied. 1995 300 Tdi Epsom Green - It's a keeper.
Wide Track Sankey- In bits- Gone to a new home
M0XQS
Post #731884 29th Sep 2018 6:29pm
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geobloke



Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4388

United Kingdom 
Hmmm interesting. Muffled Popping sounds like something air related... Worth checking the one-way valve and its rubber bung are sealing properly...

...Other than that i am left wondering about the diaphragm. Definitely worth calling up the supplier or TRW on Monday morning.

Glad the brakes are better than ever though. My servo is looking its age too... on the list... Rolling Eyes
Post #731885 29th Sep 2018 6:29pm
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donmacn



Member Since: 07 Nov 2017
Location: Nth Scotland
Posts: 1829

Yeah, that would suggest something to do with the vacuum pipework/valve to me too. As if the vaccum being created in the servo is then 'popping' as air gets in from somewhere.

It's such a simple system. I've ended up with two leaking servos. The one on the car is currently patched with dumdum paste and gorilla tape until the new one goes on, so I took the other one apart just to see how it works.

If your popping noise isn't to do with the vacuum pipe inlet valve, then I guess it's possible that the internal diaphragm has some sort of fault - but set against all of that is that the brakes are working well, which means the servo must be doing something. Donald

1994 Defender 300Tdi 110 SW - owned since 2002 - 230k miles and going strong
(The 'rolling restoration' or tinkering thread: http://www.defender2.net/forum/topic58538.html )
2000 Range Rover P38 4.0L V8

in the past..
RR classic - fitted with 200Tdi
1984 RR classic - V8 with ZF auto box
1993 Discovery 300Tdi

not to mention the minis and the Type 2 VW camper...
Post #731887 29th Sep 2018 6:40pm
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300TDi CSW Phil



Member Since: 03 Apr 2016
Location: Bracknell
Posts: 746

United Kingdom 1995 Defender 110 300 Tdi CSW Epsom Green
The servo is definitely doing a lot more than the old one.

I might nip out in the morning and double check that I have tightened everything properly and also check the check valve.

I'm assuming that there isn't anything that needed adjustment on the basis that I couldn't see anything that looked like it should be adjusted.

There is also the possibility of the "they always do that sir" and that mine wasn't hence the brakes not being as good as they are now. 1995 300 Tdi Epsom Green - It's a keeper.
Wide Track Sankey- In bits- Gone to a new home
M0XQS
Post #731888 29th Sep 2018 6:48pm
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jst



Member Since: 14 Jan 2008
Location: Taunton
Posts: 7682

2011 Defender 110 Puma 2.4 USW Stornoway Grey
run the engine with the vacuum pipe off see if the popping stops. if yes then its def in the servo and shouldnt be doing it. Cheers

James
110 XS Utility
130 Puma Station wagon/camper (in the making)
90 Puma Hardtop
Post #731909 29th Sep 2018 9:13pm
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300TDi CSW Phil



Member Since: 03 Apr 2016
Location: Bracknell
Posts: 746

United Kingdom 1995 Defender 110 300 Tdi CSW Epsom Green
So it turns out that my check valve is fine.

The connection between the check valve and the rubber hose is letting by slightly but only if I really blow hard (I will source a new bit of rubber hose).

There is adjustment on the servo push rod after all (found courtesy of Australian land rover forum). I have backed it off so there is now a little play at the pedal and the brakes seem more responsive/progressive as a result. The braking power is still as good.

The noise has not entirely gone but has reduced to about a tenth. I'm going to assume that this is "normal" and partly the slightly leaky hose and that before I couldn't hear it over the noise that must have been coming from air getting into the servo via the cracks. 1995 300 Tdi Epsom Green - It's a keeper.
Wide Track Sankey- In bits- Gone to a new home
M0XQS
Post #731954 30th Sep 2018 11:05am
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donmacn



Member Since: 07 Nov 2017
Location: Nth Scotland
Posts: 1829

Glad to hear things are better.

I did manage to fit mine just at the end of the day. No popping that I can hear, but I've got the gaiter and deadening foam off the gear lever just now - so maybe I wouldn't hear it if it was!

I did notice that there was a nut on the end of the rod inside the servo. What were the conclusions of the Australian forums - are you able to post a link? Donald

1994 Defender 300Tdi 110 SW - owned since 2002 - 230k miles and going strong
(The 'rolling restoration' or tinkering thread: http://www.defender2.net/forum/topic58538.html )
2000 Range Rover P38 4.0L V8

in the past..
RR classic - fitted with 200Tdi
1984 RR classic - V8 with ZF auto box
1993 Discovery 300Tdi

not to mention the minis and the Type 2 VW camper...
Post #732055 30th Sep 2018 8:44pm
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300TDi CSW Phil



Member Since: 03 Apr 2016
Location: Bracknell
Posts: 746

United Kingdom 1995 Defender 110 300 Tdi CSW Epsom Green
Sorry Donald, I can't find the post I was looking for on the Australian site. I can't remember what I typed in to Google to get the search result and don't appear to be able to emulate it with enough accuracy to get the result back.

However, the jist of it is that that nut you saw is the adjuster and you need a pair of pliers to hold the splined bit just behind it in order to turn it.

I also found it helped to have someone push on the brake pedal to make it more accessible.

I guess as with all things Defender tolerances are a bit larger than most modern manufacturing and therefore yours may be OK straight out of the box. As long as your brakes are now working as they should and there are no random noises then I guess everything is fine. 1995 300 Tdi Epsom Green - It's a keeper.
Wide Track Sankey- In bits- Gone to a new home
M0XQS
Post #732110 1st Oct 2018 8:19am
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donmacn



Member Since: 07 Nov 2017
Location: Nth Scotland
Posts: 1829

Thanks for trying Phil.

Just for the h*ll of it, I had a wee look myself and found this.
https://forums.lr4x4.com/topic/97934-brake-servo-freeplay/

I think the key section of text was this:

"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."


At some point in the future - probably next summer, assuming I get through the MOT in October... - I do plan to renew the front brake pipes, so I'll have the pipes off the master cylinder anyway which means I could look at this then. It's not a big deal at the moment, but if there's anything to be gained in the Defender 110 braking stakes, I'd have it. Donald

1994 Defender 300Tdi 110 SW - owned since 2002 - 230k miles and going strong
(The 'rolling restoration' or tinkering thread: http://www.defender2.net/forum/topic58538.html )
2000 Range Rover P38 4.0L V8

in the past..
RR classic - fitted with 200Tdi
1984 RR classic - V8 with ZF auto box
1993 Discovery 300Tdi

not to mention the minis and the Type 2 VW camper...
Post #732141 1st Oct 2018 10:45am
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300TDi CSW Phil



Member Since: 03 Apr 2016
Location: Bracknell
Posts: 746

United Kingdom 1995 Defender 110 300 Tdi CSW Epsom Green
Don't recall finding that one (i read so many I can't remember). The one I found was essentially the same on the aulro forum but had pictures.

I'll be taking mine for another test drive shortly so assuming all goes well I'm happy. I drove it yesterday with no issues at all but todays trip will be nearly twice the distance. 1995 300 Tdi Epsom Green - It's a keeper.
Wide Track Sankey- In bits- Gone to a new home
M0XQS
Post #732145 1st Oct 2018 11:04am
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