johnwill Posted June 9, 2020 Author Report Share Posted June 9, 2020 2 hours ago, John L said: Have you bleed the servo? Does the MC pushrod have the proper clearance, and is there a spring to return the pedal? There are other pages of the fitting instructions if needed. A picture of you servo would be helpful. Yes. I have a bleed nipple on the servo. Will check the spring anyway. Quote Link to post Share on other sites
johnwill Posted June 9, 2020 Author Report Share Posted June 9, 2020 Update: having set everything up before bleeding the brakes (including rear adjusters. I had put new shoes both sides and a new adjuster on one side) I had the problems mentioned. Checked everything again yesterday, and found one adjuster was not adjusted properly. I can only guess my test drive must have “settled” the shoes in a bit more... adjusted everything again, and used the block of wood method overnight. Just checked and I now have pressure half way down the pedal, first press, so progress made. I still intend to re-bleed farthest to nearest, and of course road test. Will see what occurs, but more promising than yesterday. Quote Link to post Share on other sites
ianc Posted June 9, 2020 Report Share Posted June 9, 2020 Stuart is spot on - bleeding has always commenced with the furthest from the master cylinder, which is left rear on a RHD TR. Ian Cornish Quote Link to post Share on other sites
johnwill Posted June 9, 2020 Author Report Share Posted June 9, 2020 16 minutes ago, ianc said: Stuart is spot on - bleeding has always commenced with the furthest from the master cylinder, which is left rear on a RHD TR. Ian Cornish Left rear? I thought furthest away from m/c should be right rear ( based on pipe length) Quote Link to post Share on other sites
johnwill Posted June 9, 2020 Author Report Share Posted June 9, 2020 57 minutes ago, ianc said: Stuart is spot on - bleeding has always commenced with the furthest from the master cylinder, which is left rear on a RHD TR. Ian Cornish From the workshop manual.... are they different for each model? Quote Link to post Share on other sites
ntc Posted June 9, 2020 Report Share Posted June 9, 2020 All that will do is push the air into pockets and is not right.It has been std practice to start at the furthest away first as Stuart said. Quote Link to post Share on other sites
ianc Posted June 10, 2020 Report Share Posted June 10, 2020 I've no idea where that sheet comes from, John. The Triumph Workshop Manual (for the TR4, but similar for other models), says on page 3.204: Bleeding Procedure 2 - remove dust cap from bleed nipple on the wheel furthest from the master cylinder (N/S rear) ……. 5 - repeat the procedure for the remaining three brakes, finishing with the wheel cylinder nearest the master cylinder (O/S front). In Britain, N/S is near side, the side nearest the pavement, so left rear. O/S is offside which is front right. Ian Cornish Quote Link to post Share on other sites
stuart Posted June 10, 2020 Report Share Posted June 10, 2020 (edited) The confusion comes from page 3-303 which covers bleeding only for when an original Moto-Vac servo is fitted which is plumbed differently and also features a bleed screw on the unit.Its extremely unlikely thats what the OP has fitted. Stuart. Edited June 10, 2020 by stuart Quote Link to post Share on other sites
stuart Posted June 10, 2020 Report Share Posted June 10, 2020 Also if its a Solid axle 4a then it is right rear first as they have a strange pipe arrangement at the rear where the main pipe goes into the left rear and out and across to right rear so there is only one bleed nipple at the rear. Stuart. Quote Link to post Share on other sites
johnwill Posted June 10, 2020 Author Report Share Posted June 10, 2020 28 minutes ago, stuart said: The confusion comes from page 3-303 which covers bleeding only for when an original Moto-Vac servo is fitted which is plumbed differently and also features a bleed screw on the unit.Its extremely unlikely thats what the OP has fitted. Stuart. Mine is a motovac, and has the bleed nipple Quote Link to post Share on other sites
johnwill Posted June 10, 2020 Author Report Share Posted June 10, 2020 25 minutes ago, stuart said: Also if its a Solid axle 4a then it is right rear first as they have a strange pipe arrangement at the rear where the main pipe goes into the left rear and out and across to right rear so there is only one bleed nipple at the rear. Stuart. Mine is IRS, and rear right is longest length of brake pipe from the m/c. Union to split between rear hubs is on l/h side of chassis. Quote Link to post Share on other sites
stuart Posted June 10, 2020 Report Share Posted June 10, 2020 (edited) 3 minutes ago, johnwill said: Mine is a motovac, and has the bleed nipple Unusual for one to have survived that long in good working condition. You still need to start from the rear furthest nipple and work forward regardless. Are you using Silicon fluid BTW? Stuart. Edited June 10, 2020 by stuart Quote Link to post Share on other sites
stuart Posted June 10, 2020 Report Share Posted June 10, 2020 1 minute ago, johnwill said: Mine is IRS, and rear right is longest length of brake pipe from the m/c. Union to split between rear hubs is on l/h side of chassis. Then start at the right rear and work forward then and let us know how you get on, if its still a bit spongy then pump the pedal up hard and jam it down and leave overnight. Stuart Quote Link to post Share on other sites
johnwill Posted June 10, 2020 Author Report Share Posted June 10, 2020 Just now, stuart said: Unusual for one to have survived that long in good working condition. You still need to start from the rear furthest nipple and work forward regardless. Are you using Silicon fluid BTW? Stuart. My original servo gave up the ghost in about 1983 and I knew a guy who got me a brand new one from Clayton Dewandre, same servo. Quote Link to post Share on other sites
stuart Posted June 10, 2020 Report Share Posted June 10, 2020 Just now, johnwill said: My original servo gave up the ghost in about 1983 and I knew a guy who got me a brand new one from Clayton Dewandre, same servo. Good find then, I havent seen a good one in quite a few years. Stuart. Quote Link to post Share on other sites
johnwill Posted June 10, 2020 Author Report Share Posted June 10, 2020 (edited) 6 minutes ago, stuart said: Good find then, I havent seen a good one in quite a few years. Stuart. According to the guy who worked there, it was their last one. Direct replacement for mine, so very easy to swap, and always followed the manual page 3-303 for bleeding. i’m guessing switching to a modern servo will require a bit more work... do the modern ones not have their own bleed nipple? Edited June 10, 2020 by johnwill Quote Link to post Share on other sites
johnwill Posted June 10, 2020 Author Report Share Posted June 10, 2020 50 minutes ago, ianc said: I've no idea where that sheet comes from, John. The Triumph Workshop Manual (for the TR4, but similar for other models), says on page 3.204: Bleeding Procedure 2 - remove dust cap from bleed nipple on the wheel furthest from the master cylinder (N/S rear) ……. 5 - repeat the procedure for the remaining three brakes, finishing with the wheel cylinder nearest the master cylinder (O/S front). In Britain, N/S is near side, the side nearest the pavement, so left rear. O/S is offside which is front right. Ian Cornish Ian, this assumes the furthest and nearest are “as the crow flies” from the m/c rather than pipe length? on pipe length, my nearest is Servo, n/s front, then o/s front, n/s rear and o/s rear. Quote Link to post Share on other sites
stuart Posted June 10, 2020 Report Share Posted June 10, 2020 6 minutes ago, johnwill said: According to the guy who worked there, it was their last one. Direct replacement for mine, so very easy to swap, and always followed the manual page 3-303 for bleeding. i’m guessing switching to a modern servo will require a bit more work... do the modern ones not have their own bleed nipple? Modern versions dont have a dedicated bleed, you could swap pretty easy but if you do dont buy a cheap one as they dont last. I still say try bleeding furthest away first for a start and see how it goes. Stuart. Quote Link to post Share on other sites
stuart Posted June 10, 2020 Report Share Posted June 10, 2020 1 minute ago, johnwill said: Ian, this assumes the furthest and nearest are “as the crow flies” from the m/c rather than pipe length? on pipe length, my nearest is Servo, n/s front, then o/s front, n/s rear and o/s rear. Ian is quoting for TR4 different to 4a at the rear. You need to start Right hand rear then left rear then right front then finally left front then if needed servo last. Quote Link to post Share on other sites
johnwill Posted June 10, 2020 Author Report Share Posted June 10, 2020 (edited) 35 minutes ago, stuart said: Modern versions dont have a dedicated bleed, you could swap pretty easy but if you do dont buy a cheap one as they dont last. I still say try bleeding furthest away first for a start and see how it goes. Stuart. I am starting to wonder if my servo is starting to fail, given it’s age. My last one failed quite obviously, cloud of white smoke out the exhaust and no brakes ! i’ve seen the warnings about cheaper servo’s on the other threads, so if I do go that route, will find some extra pennies. will try everything else first though. Edited June 10, 2020 by johnwill Quote Link to post Share on other sites
Andy Moltu Posted June 10, 2020 Report Share Posted June 10, 2020 I would concur it's the furthest away to bleed first. In terms of pipe length as some cares do have puzzling routing of brake pipes. Workshop manuals are not immune to typos. Quote Link to post Share on other sites
Waldi Posted June 10, 2020 Report Share Posted June 10, 2020 John, new shoes can be a bit spongy. If you pull the handbrake fully tight, Does this give much improvement? A little is normal, but if a lot, the shoes need to bed in or the adjustment set a bit tighter. Rock the wheel a couple of times back and forth during adjusting, this will help setting the shoes in the correct position. Quote Link to post Share on other sites
ianc Posted June 10, 2020 Report Share Posted June 10, 2020 Even if I had not removed and thrown away the servo which was on 4VC when I acquired it in 1969, all this would convince me that such a device just complicates matters and is unnecessary. I was not aware that the solid axle TR4A, such as Stuart's, is plumbed differently for the rear brakes - one lives and learns! Ian Cornish Quote Link to post Share on other sites
keith1948 Posted June 11, 2020 Report Share Posted June 11, 2020 Hello John Just a couple of ideas. I once had the master cylinder fail because the spring inside it broke. Also had problems in the past bleeding the brakes. I now make sure the rear wheel cylinder pistons are pushed right in and held in place with a clamp and the front calliper pistons are also pushed in and clamped. This minimises the chance of air being trapped inside them. Hope you get it sorted and share the cause because I know another TR owner with failed brakes. Keith Quote Link to post Share on other sites
johnwill Posted June 15, 2020 Author Report Share Posted June 15, 2020 Update: I put the new m/c back on, checked all brake line connections, no leaks but pinched them up a fraction more, re-bled a couple of times and then blocked the pedal down (also tightened rear adjusters) and left for a couple of days. pedal felt firmer on first push, not to floor, so took it for a test drive. Brakes working well, pedal half way down. will let everything bed down for some miles, and then may re-bleed again. hopefully sorted now, so thanks for all the advice. john Quote Link to post Share on other sites
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