Jersey Royal Posted November 9, 2008 Report Share Posted November 9, 2008 Hi All, I have fitted new servo from Tr Shop, very quick delivery. System bleed and i found when i took it for a run that the pedal only operated in about two thirds of its travel. Having now consulted the Haynes manual, i should have checked the clearance between end of pushrod and Master. Put a rule across end of servo and adjust endbolt to give 0.001---0.016 in, should also use loctite on the threads. This is an easy error, and had not read about it on the forum, hence this post Any one made admit to the same blunder. Cheers Guy Quote Link to post Share on other sites
88V8 Posted November 9, 2008 Report Share Posted November 9, 2008 So, you had a lot of free travel - I had just a tiny bit of free travel so I didn't bother to check the clearance, but no Loctite, oops Quote Link to post Share on other sites
Jersey Royal Posted November 9, 2008 Author Report Share Posted November 9, 2008 (edited) but no Loctite, oops Ivor, Why no Loctite? Haynes does say to use Grade B Loctite. Cheers Guy Edited November 9, 2008 by Jersey Royal Quote Link to post Share on other sites
TIMS Posted November 9, 2008 Report Share Posted November 9, 2008 Guy Thanks for that one. Replacement servo is in the garage and on my list for fitting in the next couple of months. I had not known about the clearance check before your posting. Again, thanks. Regards Tim Quote Link to post Share on other sites
88V8 Posted November 9, 2008 Report Share Posted November 9, 2008 Why no Loctite? Haynes does say to use Grade B Loctite. I used the Brown Bible which says nothing about clearance nor Loctite I think whoever said recently that the author of the Brown Bible coughed up the absolute minimum of information, got it about right. Ivor Quote Link to post Share on other sites
Tony Millward Posted November 10, 2008 Report Share Posted November 10, 2008 Thanks for the heads up Guy. I also bought one from the TR Shop (also fast delivery here in Australia), to be fitted. I would have missed this. Cheers Tony Quote Link to post Share on other sites
Jersey Royal Posted November 12, 2008 Author Report Share Posted November 12, 2008 Hi All, Just completed the adjustment, it was suprisingly easy. On the end of the pushrod is a threaded rod with domed nut on the end of it and a further nut, screw this out to suit tolerances and turn back nut to tighten to pushrod. I imagine the originals are the same but mine was rusted up so left it. What an improvement, brakes now really sharp,all four wheels lock up without much problem. Just for those contemplating fitting new servo Guy Quote Link to post Share on other sites
John L Posted November 17, 2008 Report Share Posted November 17, 2008 Guy What sort of clearance did you set it to, 0.001 - 0.016" is quite a large band, this then just a straight edge across where the studs are? Regards John Quote Link to post Share on other sites
Jersey Royal Posted November 17, 2008 Author Report Share Posted November 17, 2008 GuyWhat sort of clearance did you set it to, 0.001 - 0.016" is quite a large band, this then just a straight edge across where the studs are? Regards John John Straight edge across by studs, and i have sey mine at .010. Which seems much improved althogh i think i could reduce it a little more. Although at present car is in bits , when all together i will readjust a little more. Still cant believe how much better the brakes are since fitting new servo. Its one of those things you get used to, just like when i replaced clutch, felt like a new gearbox and car runs much better. Cheers Guy Quote Link to post Share on other sites
roulli Posted November 17, 2008 Report Share Posted November 17, 2008 John, don't set the play too tight. I did the same exercise once on my TVR S3C, and after a few miles the brakes seized, due to thermal expansion of the brake system. I had to release the nuts fixing the MC to the Servo by one turn to get home again... Cheers, Patrick Quote Link to post Share on other sites
Mk2 Chopper Posted October 8, 2018 Report Share Posted October 8, 2018 (edited) I had a different problem to the OP, after replacing the MC, I had trouble bleeding - no fluid coming through, cured by releasing the MC from the servo, then after bleeding i took it for a short test run to find the front brakes not releasing and getting progressively tighter. So then I'm thinking is the servo push rod already pushing the MC piston in a little at rest, again I release the MC from servo, bolt back down and now the brakes are free. But I'm thinking maybe it's only just working and could again lock up, so i check the servo clearance as per the Haynes (as noted nothing in Brown Bible) and it's right on spec. So I then compare the new MC to the old one and discover the piston retracts further out than the old one, it has indeed been slightly pressing the brakes on, probably causing the no fluid when dry and then the brake staying on when fluid is present because it couldn't retract to allow the intake of fluid/release of pressure. After adjusting the servo push rod means of a thin bit of brushed on paint on the end of the push rod until I just got a bit of transfer to the MC, I've got my air gap between them, not exactly the best way but the pedal feels good still. Maybe I should have rebuilt the original MC afterall. Gareth Edited October 8, 2018 by Mk2 Chopper Quote Link to post Share on other sites
KiwiTR6 Posted October 8, 2018 Report Share Posted October 8, 2018 5 hours ago, Mk2 Chopper said: I had a different problem to the OP, after replacing the MC, I had trouble bleeding - no fluid coming through, cured by releasing the MC from the servo, then after bleeding i took it for a short test run to find the front brakes not releasing and getting progressively tighter. So then I'm thinking is the servo push rod already pushing the MC piston in a little at rest, again I release the MC from servo, bolt back down and now the brakes are free. But I'm thinking maybe it's only just working and could again lock up, so i check the servo clearance as per the Haynes (as noted nothing in Brown Bible) and it's right on spec. So I then compare the new MC to the old one and discover the piston retracts further out than the old one, it has indeed been slightly pressing the brakes on, probably causing the no fluid when dry and then the brake staying on when fluid is present because it couldn't retract to allow the intake of fluid/release of pressure. After adjusting the servo push rod means of a thin bit of brushed on paint on the end of the push rod until I just got a bit of transfer to the MC, I've got my air gap between them, not exactly the best way but the pedal feels good still. Maybe I should have rebuilt the original MC afterall. Gareth I had a similar problem Gareth, but it was the tilt valve that was the culprit. The MC had been fitted with a s/steel liner prior to my ownership but the opening for the tilt valve wasn't cut back fully to match the original hole. This prevented the tilt valve from opening properly when the pedal was released. Easing the liner with a small grinder to match the original hole solved the problem. Gavin Quote Link to post Share on other sites
Mk2 Chopper Posted October 9, 2018 Report Share Posted October 9, 2018 Wow that must have taken a while to figure out what was going on. I just assumed a replacement MC would be set up as per factory, pretty vital component too. Gareth Quote Link to post Share on other sites
John McCormack Posted October 9, 2018 Report Share Posted October 9, 2018 On 11/10/2008 at 11:02 AM, Tony Millward said: Thanks for the heads up Guy. I also bought one from the TR Shop (also fast delivery here in Australia), to be fitted. I would have missed this. Cheers Tony Hi Tony, Another here downunder with a couple of TRs. I have a 1970 TR6 CP51049 and two TR2s, TS5038O and TS3732O. Are you a TR Register Australia member? Cheers John Quote Link to post Share on other sites
KiwiTR6 Posted October 10, 2018 Report Share Posted October 10, 2018 (edited) 17 hours ago, Mk2 Chopper said: Wow that must have taken a while to figure out what was going on. I just assumed a replacement MC would be set up as per factory, pretty vital component too. I was fortunate that a member of this forum (no longer though) suggested the tilt valve as the likely culprit and went from there. Edited October 10, 2018 by KiwiTR6 spelling Quote Link to post Share on other sites
reginald Posted October 10, 2018 Report Share Posted October 10, 2018 Hi I had the same issue a few years back and discoverd it was the piston but mine was too short compared to the original so gave long pedal travel and bleeding issues so I compared it to the original what the clearance should be And reset the servo push rod to suit and it worked fine. The clearance I gather is there so the piston can return fully with no interferance, so within reason As long as there is the correct clearance it will be fine, I don t think the manufacturers relise the importance of the piston lengh/depth in the TR6 aplication. Regards Richard Quote Link to post Share on other sites
Mk2 Chopper Posted October 11, 2018 Report Share Posted October 11, 2018 I guess the check in the Haynes is only to be taken with original MC, but any replacement needs the pushrod to be checked and matched to the new MC Quote Link to post Share on other sites
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