Rychu Posted May 30, 2023 Share Posted May 30, 2023 Hi everyone, I hope someone is able to help me and I thank you all in advance for any advice. The brakes work but the pedal travel is long. Normally I would expect this to be air in the system but I have tried bleeding many times to no avail. However I have noticed that if I apply the handbrake a couple of notches the pedal travel becomes significantly less. Any ideas? Regards Richard Quote Link to comment Share on other sites More sharing options...
Clive Posted May 30, 2023 Share Posted May 30, 2023 Have you adjusted the rear brakes? (and what car) If a spit/herald/Vit/GT6 then the way to do it is disconnect the brake cable from the lever at the back of the drums, and then adjust up the manula adjuster until the drums are locked solid. I then move the lever with a screwdriver to "apply" the handbrake, in case it hasn't moved fully. Check still locled solid, back the adjuster off until the drums can just rotate freely. People often adjust the handbrake cable, so the first dab of the brake takes up the freeplay. Cable is adjusted AFTER the brake adjuster has been set. That is the most likely cause from your symptoms. If not, ask again. Quote Link to comment Share on other sites More sharing options...
Rychu Posted May 30, 2023 Author Share Posted May 30, 2023 Thanks Clive. So when the handbrake is off should the handbrake cable be taught as at the moment it is slack? Quote Link to comment Share on other sites More sharing options...
glang Posted May 30, 2023 Share Posted May 30, 2023 Cable should be slightly slack but the shoes in the drums have to be adjusted as close as possible to the drum inner surface without rubbing. This ensures that on pressing the pedal the rear brakes start to work almost immediately.... Quote Link to comment Share on other sites More sharing options...
standardthread Posted May 30, 2023 Share Posted May 30, 2023 49 minutes ago, Rychu said: So when the handbrake is off should the handbrake cable be taught as at the moment it is slack? Triumph and Standard handbrakes are S H one T, so I would say yes, but not to the point where the shoes drag on the drums. Quote Link to comment Share on other sites More sharing options...
Rychu Posted May 30, 2023 Author Share Posted May 30, 2023 (edited) I normally adjust until the brake fully activates then back off 2 clicks but this doesn’t cure the problem. I assume therefore the handbrake cable is too loose? Thank you for all your replies. im hoping to get her back on the road this weekend after a few years in the garage. Edited May 30, 2023 by Rychu 1 Quote Link to comment Share on other sites More sharing options...
Clive Posted May 30, 2023 Share Posted May 30, 2023 17 minutes ago, Rychu said: I normally adjust until the brake fully activates then back off 2 clicks but this doesn’t cure the problem. I assume therefore the handbrake cable is too loose? No, the loose handbrake cable will have zero effect on the footbrake. It may make the handbrake lift too many clicks though. Other causes could be the wheel cylinder not moving freely. Looks like you need to pop the brake drums off, and check everything moves as it should. If you get carried away, taking the shoes off and the U clips for the wheel cylinder, so you can clean everything up and smear some copper grease can pay dividends. Quote Link to comment Share on other sites More sharing options...
glang Posted May 30, 2023 Share Posted May 30, 2023 Why do back off two clicks? Just adjust until you can still turn the drum without rubbing (in fact I even allow a slight rub just get the shoes as close as possible to the drum). This is the best you can do for the brake pedal and I still wasnt happy so I fitted a larger bore master cylinder. This means pedal push is harder but Im strong and movement is now perfect... Quote Link to comment Share on other sites More sharing options...
Rychu Posted May 31, 2023 Author Share Posted May 31, 2023 But what I do not understand is why when I apply the handbrake slightly the pedal travel is much shorter? Hence my thinking that the handbrake cable is too loose. Quote Link to comment Share on other sites More sharing options...
glang Posted May 31, 2023 Share Posted May 31, 2023 Cable nothing to do with foot brake. When you apply handbrake slightly the shoes are pulled in closer to drum and the pedal then doesnt need to travel so far to push them fully into contact with drum. This is why the closer you can get the shoes to the drum with their adjuster (not handbrake cable adjuster) the less pedal travel youll have... Quote Link to comment Share on other sites More sharing options...
JohnD Posted June 1, 2023 Share Posted June 1, 2023 Another reason for a long travel could be too small diameter a master cylinder. Ryuchu, have you or the DPO replaced the M/c? Should be, I think, 0.7". A larger cylinder displaces more fluid per millimeter of travel, so shorter. But you may need to press a bigger M/c harder for the same braking effect! John Quote Link to comment Share on other sites More sharing options...
Rychu Posted June 1, 2023 Author Share Posted June 1, 2023 Thanks chaps. I have tried winding the adjuster fully on then only slightly backing off but it makes no difference. The master cylinder (dual circuit) and complete braking system was replaced 8 years ago when the car was restored but from memory the problem was the same with the previous cylinder. Although I do recall years ago I jacked the rear end up as high as I could and left it for a while then bled the brakes and the pedal travel was much shorter. This makes me believe it is air in the system but bleeding makes no difference and as I said when I slightly apply the handbrake the pedal travel is shorter. I’m not stupid, although some may disagree, but this has me stumped. Does anyone know someone in the Basingstoke area who might be able to have a look as my lad wants to be able to use the car so I want the brakes to be as good as possible. Quote Link to comment Share on other sites More sharing options...
glang Posted June 1, 2023 Share Posted June 1, 2023 Ahhh dual circuit makes things a bit more complicated. Air in any system though makes the pedal spongy and you can make it more solid by repeated rapid presses. While poor adjustment of the shoes gives long travel but then solid pedal. Operating hand brake will help in second case but in first pedal will still be spongy.... Quote Link to comment Share on other sites More sharing options...
JohnD Posted June 1, 2023 Share Posted June 1, 2023 Ryachu, It really, really helps if you give essential details when asking Qs on any website. You're not stupid, but others aren't psychic! For instance, Canley's list at least FOUR different M/cs for Triumphs, and there are many more out there, that your DPO could have fitted! Pictures? And "long travel" is not the same as "spongy pedal"! Ensure that your brake drums are correctly adjusted, forget the hand brake for now, that has a completely different adjustment, come back and tell us how you get on. John Quote Link to comment Share on other sites More sharing options...
Rychu Posted June 1, 2023 Author Share Posted June 1, 2023 Hi guys, the problem is purely long pedal travel. The brakes are not spongy. Canleys only list one tandem cylinder for my car, this one: https://www.canleyclassics.com/?catalogue=triumph-spitfire-mkiv/1500&diagram=triumph-spitfire-mkiv/1500-brake-master-cylinder-tandem-2 This is the same as the original and not the one with the larger cap and wider reservoir used on earlier 1500s. Quote Link to comment Share on other sites More sharing options...
glang Posted June 1, 2023 Share Posted June 1, 2023 Yes I dont think there are many variations available for the tandem system like those for a single master cylinder. Have the front calipers been rebuilt or replaced recently? There has been a problem with some where the pistons get pulled back too far by the seals which means more pedal travel is required to get them to bite the next time. This has driven people mad trying to find the cause but dont know if it was with your type of calipers... 1 Quote Link to comment Share on other sites More sharing options...
Rychu Posted June 2, 2023 Author Share Posted June 2, 2023 Hi Glang, the callipers were replaced when the car was restored but the problem was evident before and after this. Quote Link to comment Share on other sites More sharing options...
glang Posted June 2, 2023 Share Posted June 2, 2023 Not familiar with bleeding dual systems but believe you have to be careful not to operate the pressure differential switch so best to do with vacuum or pressure bleed as then the pedal doesnt have to operated... Quote Link to comment Share on other sites More sharing options...
JohnD Posted June 2, 2023 Share Posted June 2, 2023 13 hours ago, Rychu said: Hi guys, the problem is purely long pedal travel. The brakes are not spongy. Canleys only list one tandem cylinder for my car, this one: https://www.canleyclassics.com/?catalogue=triumph-spitfire-mkiv/1500&diagram=triumph-spitfire-mkiv/1500-brake-master-cylinder-tandem-2 This is the same as the original and not the one with the larger cap and wider reservoir used on earlier 1500s. Thanks, Rychu, that's the way to do it! Yes, it is! I think with others above that adjusting your rear drums may be the way forward. Good luck! John Quote Link to comment Share on other sites More sharing options...
Martins Stag Posted June 2, 2023 Share Posted June 2, 2023 Dual circuit was only availible on very late 1500 as has been said. On some master cylinder you can get an adjustable operating rod that operates under the the rubber boot on the bulk head. It may be worth checking that there is not too much play in this. On my 1500 many years ago the hole had worn oval giving me too much travel... Just a thought... Quote Link to comment Share on other sites More sharing options...
Wendy Dawes Posted June 2, 2023 Share Posted June 2, 2023 Try loosening the master cylinder cap and wedge your brake pedal down to the floor overnight then release it the next day and tighten the cap and see what that does. it’s usually very effective in removing stubborn air from hydraulic systems Quote Link to comment Share on other sites More sharing options...
Wendy Dawes Posted June 2, 2023 Share Posted June 2, 2023 It also works on air in the clutch system Quote Link to comment Share on other sites More sharing options...
Rychu Posted June 2, 2023 Author Share Posted June 2, 2023 Thank you for all your help. I think I need to investigate further and I will bear all your suggestions in mind 👍 Quote Link to comment Share on other sites More sharing options...
standardthread Posted June 2, 2023 Share Posted June 2, 2023 There was a thread on the Dolomite forum a few years when I was looking at replacing a tandem master and I thought, and posted,that I would give the pedal a good thump to bleed the brakes. I was told not to do this because it could damage a bakalite part in the servo, and the way to bleed the brakes was to open all the bleed screws and let gravity do the job at first. Then close the bleed screws and bleed each brake conventionally once there was fluid in the lines. Something to do with air getting trapped in the lines as you bleed one? Quote Link to comment Share on other sites More sharing options...
Auldman Posted June 4, 2023 Share Posted June 4, 2023 There are two important signs you descibe, Rychu 1.extensive pedal travel. 2.It reduces when the handbrake is applied Consider 1.This is not a sign that air is in the system - that would be sponginess - or more specifically, excessive travel is greatly improved for a moment by “pumping” the pedal. Consider 2.- here lies the answer. Pulling on the handbrake shifts the shoes taking up any excessive travel, and it also allows the slave cylinder to slide in the back plate ( as it should) and the travel will be reduced. So we are looking at the rear brakes ( any concerns re the fronts can be quickly assessed by careful clamping of the front brake hoses and then trying the pedal) adjusters - If the all the components of the adjusters aren’t fully free ( a very common fault) proper adjustment just isn’t possible as you cant take up free- play. slave cylinder - It isn’t widely appreciated that this has to be free to slide in the back plate as the foot brake and or handbrake is applied.It gets stuck up- like the adjusters do.( It can reduce handbrake efficiency a lot) The answer is to dismantle, check everything, free everything off and work in anti- seize like Copa Slip. The aim is to have the adjusters freed off to the extent light finger pressure with a short spanner will allow them to function. The slave cylinder is held, ( but has to be able to slide) in the back plate held be two interlocked by horseshoe shaped type clips. This needs the same approach , dismantle, free-off clean and copper grease. Good luck… 1 Quote Link to comment Share on other sites More sharing options...
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