Member Since: 29 Aug 2022
Location: Dublin
Posts: 21
Brakes locking - Installed new Brake Servo, master cylinder
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UPDATED:
Hi All
I replaced my 2006 Disco 3 - brake servo, master cylinder , brake booster vacuum pipe, DOT4 over the weekend.
I used ( see picture) DOT 4 ISO4925 Class4 , FMVSS116 DOT4 as the new brake fluid as I couldnt find the original LR spec class 6, and most auto shops never heard of class 6, so only supply class 4.
This seems to be fine to use based on my research and replies below.
I have only used the Discovery twice since doing the job, and the 1st time driving along after about 20 minutes of driving I could feel braking resistance as I drove along which kept getting stronger until I had almost full brake resistance, felt like it was from the rear....pulled over checked the parking brake etc all fine, but started it again and still had almost full brake resistance.
Plugged in the IID tool and it lit up with all sorts of new errors.
This error wasn't there before doing the servo, vacuum pipe, master cylinder and bleed works.
Topix extract (attached) suggests the fluid I have should be OK, and the parking brake seemed fine.
I left the Disco beside a church until later that evening, managed to drive it home when there was hardly any traffic ( so less braking required on the journey) but it began locking up again, just as I got to outside my house.
Last night I took it for a trip to the local shop, no issues getting there, but coming back I had resistance again and when I check this time the from wheel hubs were very hot after a 10 minute short journey.
I saw some US based YouTube videos suggesting the brake servo pin néeds to be adjusted and measured with a tool when you swap out the servo, but I don't see any adjuster on the end of the TRW servo like shown on American YouTube videos for non land rover cars.
Does anyone have the workshop procedure for this please as this was a recall issue (P017), and someone had shared the.Workshop procedure on this forum previously?
The workshop procedure referred to os GTR workshop procedure section 206-06 (master cylinder) and 206-07 (new brake booster).
Last edited by GLEOIRL on 8th Jun 2023 9:20 am. Edited 2 times in total
6th Jun 2023 2:36 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10676
I doubt it’s to do with the different in class of fluid.
6th Jun 2023 2:53 pm
KevinD3
Member Since: 05 Aug 2020
Location: Sutton Coldfield
Posts: 1277
Hey mate, as above, class 4 is what the handbook states so should be no issues on that.
Weird that they’re locked ON, air in the system usually results in soft brakes and less braking not more.
May be worth doing a quick brake bleed in situe to see if it gets you home. Back brakes on suggests parting brake not releasing rather than foot brake issue maybe?
Click image to enlarge
2008 HSE Stornoway Grey
My Wife thinks the D3 is a hobby, The D3 thinks the wife is 💕
6th Jun 2023 3:50 pm
GLEOIRL
Member Since: 29 Aug 2022
Location: Dublin
Posts: 21
Thanks for this additional information and for confirming the fuild is an OK spec. The parking brake seems fine too,
I'll use the IIDTool again later for an in Situ module bleed again.
6th Jun 2023 4:29 pm
GLEOIRL
Member Since: 29 Aug 2022
Location: Dublin
Posts: 21
Does anyone have a copy of these two workshop procedures for recall P017 please, to allow me see if the brake booster pin can be adjusted?
Click image to enlarge
Parts used :
Click image to enlarge
Click image to enlarge
8th Jun 2023 9:24 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10676
Trw can be counterfit or have batch problems. So consider fitting old parts. To see if fault goes
The TSB just says fit 2 pipes to the value pump at rear of engine. Unrelated
8th Jun 2023 1:30 pm
GLEOIRL
Member Since: 29 Aug 2022
Location: Dublin
Posts: 21
I rang TRW UK tech support, and she suggested the part was legitimate and that the brake servo pin shouldn't need any adjustment as it's specific to the LR D3, but that there are a few different part numbers, and I might have been provided with the incorrect one for my reg number, but she could xref my Irish reg plate so she couldn't clarify.
That said the photos above of the parts show they do we the dates for a 2006 model and my VIN :SALLAAA136A392352
This afternoon I checked and re-bled each caliper and also electronically disconnected the parking brake fuse, ensured the wheels were moving OK, and drive the Disco again this afternoon, and again it locked up after about 20 minutes use.
8th Jun 2023 1:43 pm
Marshall8hp
Member Since: 05 Dec 2022
Location: Townsville
Posts: 34
OK, so my truck had a new TRW master cylinder fitted, and I experienced exactly the same problems you describe. It seems that the push rod in the vacuum unit is a tad too long, which doesn’t allow the MC to fully return, meaning the brakes pump up over time. You can either:
Machine a tiny amount off the push rod …. Or
Do what I did, replace the new TRW MC with a genuine LR MC, in a LR box. No more issues since, good as gold.
(Any one want an almost new TRW MC? Only done 500km ….
9th Jun 2023 5:45 am
GLEOIRL
Member Since: 29 Aug 2022
Location: Dublin
Posts: 21
Interesting thanks - I might swap test back on the old master cylinder then and try that again as it was oil in the old brake servo and vacuum hose at fault prior to swap out the old master cylinder was fine.
I was also wondering perhaps if I over tensioned the bolts on the master cylinder where it bolts onto the servo housing as perhaps just a few mm overtightened affects the servo pin.
I was struggling to find the specific Disco3 torque settings for the master cylinder bolts, so I'll see if they are any tighter than my Defender equivalents, which I see should be spec'd at 26NM (also TRW parts on my Puma Defender).
9th Jun 2023 8:48 am
craig_bennett
Member Since: 05 Oct 2012
Location: Bristol
Posts: 52
Hi did you get this resolved ?
If so how ?
Ive been having the same issue.
Ive blown 2x master cylinders and fitted a new servo. (All trw). The problem still continues i cant understand why it does it. Thanks craig.craig.
15th Apr 2024 12:39 am
Globetrotter448
Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1818
The fluid is not returning to the master cylinder so eventually applies the brakes. Check that there is some play in the brake pedal, if none, then the master cylinder is not fully returning. As said previously, sometimes better to go with originals.
15th Apr 2024 10:04 am
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20841
Marshall8hp wrote:
replace the new TRW MC with a genuine LR MC, in a LR box. No more issues since, good as gold
Member Since: 21 Oct 2016
Location: kent
Posts: 14129
KevinD3 wrote:
Hey mate, as above, class 4 is what the handbook states so should be no issues on that.
Weird that they’re locked ON, air in the system usually results in soft brakes and less braking not more.
May be worth doing a quick brake bleed in situe to see if it gets you home. Back brakes on suggests parting brake not releasing rather than foot brake issue maybe?
Click image to enlarge
Hi mate
Really hope u don’t think I’m being pedantic or rude in any way but see it should be class 6 and not class 4
If it also helps any newbies for brake fluid I’ve used ATE SL6 brake fluid
15th Apr 2024 12:22 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14129
Disco_Mikey wrote:
Marshall8hp wrote:
replace the new TRW MC with a genuine LR MC, in a LR box. No more issues since, good as gold
This
Hiya
Hope ur good, well every day is a school day , sounds like a similar story in comparison of manufacturers, ie - where some fit a non genuine alternator instead of a Denso
Admittedly never heard of the fluid not returning to the master cylinder before , assume that down to failing seals etc
Many thks
15th Apr 2024 12:31 pm
craig_bennett
Member Since: 05 Oct 2012
Location: Bristol
Posts: 52
Thanks for the replies guys. Its possable it could be faulty parts, although it has happened with my original servo and a brand new trw master and then again with a new trw servo and a second new trw master. Could i be that unlucky to get dodgy ones twice? I used trw as they where the oem manufacturer on the original landrover units I removed. Do you think trw now have quality issues or fake parts. The parts came from known suppliers. Thanks again.craig.
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i cant understand why it does it. Thanks craig.
