DanMi Posted February 21, 2019 Report Share Posted February 21, 2019 I'd also put new seals in the master cylinder and check the rear hoses/cylinders. There's nothing worse than bleeding the system only to find a leak from somewhere else a few weeks later. Plus lets be realistic if the front hoses are perished there's a very good chance the rears are old too. 1 Link to comment Share on other sites More sharing options...
johny Posted February 21, 2019 Report Share Posted February 21, 2019 The steering flexible coupling is a potential safety critical weak point but you raise an interesting point about replacing stuff that many people dont consider: The bath tub curve. This is a graph that describes the statistical failure rate of a item and unsurprisingly forms a bath shape in that there tends to be a lot of failures at the start of its usage. Then as time passes the failure rate reduces and stays lower until the end of its life when the number of failures increases again. All this means that there is a certain risk when you replace any component that you are removing something that is in the lowest stage of the curve and returning to the start with a much higher risk of failure. This higher risk includes, as in Marks case, incorrect installation or it can be a defect in the new component itself from design, quality or manufacturing issues. Its something thats taken very seriously in industry and we should consider because quite often the risk of an item failing can be, paradoxically, greater if we replace it! 1 Link to comment Share on other sites More sharing options...
Gnbickley Posted February 21, 2019 Author Report Share Posted February 21, 2019 Gentlemen, Thank you for all the advice. Unfortunately I'm on a very very tight budget and I can't afford to buy new or recon calipers from anywhere it's simply not an option at present. So I ordered new stainless steel braided hoses and caliper repair kits from Canley yesterday and it all arrived today. I'm hoping to get everything fitted over the weekend and get the front brakes sorted. DanMi, I got new hoses for the rear brakes as well as I'm going to overhaul them once I've got the fronts sorted. 1 Link to comment Share on other sites More sharing options...
johny Posted February 21, 2019 Report Share Posted February 21, 2019 will you try just the hoses so, out of interest, we can positively identify the problem or just do everything at once while the system is drained? 1 Link to comment Share on other sites More sharing options...
Gnbickley Posted February 21, 2019 Author Report Share Posted February 21, 2019 Johny, I'm inclined to do the hoses and see if it makes a difference if not then I'll do the calipers. Link to comment Share on other sites More sharing options...
johny Posted February 21, 2019 Report Share Posted February 21, 2019 Great let us know how you get on... 1 Link to comment Share on other sites More sharing options...
Gnbickley Posted July 3, 2021 Author Report Share Posted July 3, 2021 Well it's taken me a little while to sort the brakes but happily I can confirm I finally got them fixed. First I replaced the hoses with steel braided ones but that didn't fix the problem so next I removed the calipers and purchased rebuild kits. Unfortunately the pistons were completely seized on the calipers and nothing in my arsenal could convince them to move! I therefore decided to buy new calipers and while I was at it I got new hoses, drums and shoes for the rear. Everything now works perfectly and I've been able to enjoy the sunshine over the last few weeks 😊 Thank you to everyone on here who commented offering advice and help it was very much appreciated and useful. Apologies for not updating you all sooner but she hasn't long been fixed. Link to comment Share on other sites More sharing options...
Patrick Taylor Posted July 23, 2021 Report Share Posted July 23, 2021 I've just picked up this thread -I'm glad everything is fixed and you are enjoying the car! Some of the earlier posts remind me of the old adage of 'before you make it go, you need to make it stop', i.e. improve the brakes before you improve the engine. I had a braided hose fail a number of years ago: I think they are PTFE tube under the stainless, and I thought they were 'fit and forget'. Apparently not! I replaced them (with more braided...) but read somewhere that in NZ braided hoses have to be replaced every seven-years... Link to comment Share on other sites More sharing options...
SpitfireGeorge Posted June 8 Report Share Posted June 8 Hi Guys, I have replaced every brake part on my Spit mk3, it is now a completely new system. My front calipers are locking on but I can free them if I undo the bleed valve. The hoses are braided and have had about 1 mile of use so they should be OK. The master cylinder seems fine and the calipers are also new and not rusted in any way. The pistons are very tight though and I had to use a vice to force them back in. Do you think I am right in suspecting the new calipers are the problem? Cheers Brett Link to comment Share on other sites More sharing options...
johny Posted June 8 Report Share Posted June 8 If it was the pistons stuck surely they wouldnt release with the loosening of the bleed valves? Are the rear drums similarly affected? Have you got a servo fitted and does it act on all the brakes? Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 8 Report Share Posted June 8 9 minutes ago, johny said: If it was the pistons stuck surely they wouldnt release with the loosening of the bleed valves? Are the rear drums similarly affected? Have you got a servo fitted and does it act on all the brakes? Agreed; that sounds more like hydraulics. Is it both calipers, or just one? When you forced the pistons back in, was this against a restricted flow of fluid thereby they seemed stiff... wonder if they're any easier when the hose is removed, but with the bleed nipple screwed in? Might be worth a try, then you can remove sticking pistons or poor calipers from your problem. You will probably have to remove each hose and check in turn, because pedal pressure is forcing fluid one way, but the release isn't letting it flow back again, so something is causing a blockage. Link to comment Share on other sites More sharing options...
SpitfireGeorge Posted June 8 Report Share Posted June 8 Thanks Guys I will check and let you know. Out shopping with the Mrs at the moment. Cheers Brett Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 8 Report Share Posted June 8 cheapest option is do check there is free play/float in the pedal pushrod if the pedal is not fully returning or its back stop /switch is incorrectly set you will not release the line pressure ,seized pedal pivot bushes can also affect this the pedal must fully return and the push rod is a a good loose rattling fit . Pete Link to comment Share on other sites More sharing options...
dannyb Posted June 8 Report Share Posted June 8 This happend to me on the Spit a couple of years ago. Had to let some fluid out of front disc break to release pressure then ride back home on just the hand brake. It turned out to be the master cylinder. Danny Link to comment Share on other sites More sharing options...
SpitfireGeorge Posted June 8 Report Share Posted June 8 If it turns out to be the master cylinder how do I adjust the pushrod? Cheers Brett Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 8 Report Share Posted June 8 there is little to adjust its controlled by the m cyl mounting bracket and the pedal stop/ switch seized pedal pivots are quite common , pete Link to comment Share on other sites More sharing options...
SpitfireGeorge Posted June 9 Report Share Posted June 9 Hi Guys, Determined it is the master cylinder as the other front brake has the same problem. If I detach the master cylinder from the brake pedal the wheels free up. Pulling the master cylinder fork forward releases the pressure and the wheels revolve freely. The MC fork is as far back towards the MC as it will go and the brake pedal lever touches the bulkhead next to the lever and will not go any further forward. When I attach the fork the brakes start dragging as I have to push the MC rod in. I need to loose at least half the diameter of the attachment hole. I was thinking of filing a cut out in the brake pedal to stop it touching the bulkhead before the pressure is fully released. Cannot really see another way of adjusting the assembly. I could buy some 5mm alloy plate and make a distance piece to sit between the MC and its bracket to pull the whole MC back. What do you think? Cheers Brett Link to comment Share on other sites More sharing options...
johny Posted June 9 Report Share Posted June 9 I think Id try to find why this is happening Brett as if everything is standard and correctly installed it shouldnt. A bodge of a bodge has got to be the last resort😲 Link to comment Share on other sites More sharing options...
SpitfireGeorge Posted June 9 Report Share Posted June 9 I am just wondering if the mounting bracket is slightly wrong dimension, possibly the MC rod is slightly too long etc and all these minor descrepancies just add up to a problem in the overall fit? Link to comment Share on other sites More sharing options...
johny Posted June 9 Report Share Posted June 9 Can you post photos of the set up and perhaps we can identify which component is wrong? Link to comment Share on other sites More sharing options...
chrishawley Posted June 9 Report Share Posted June 9 Aha! I hope I'm right in asumming that, in essence, the problem is that the push rod is too long. If the new MC came fitted with a push rod then it may be the wrong length for this particular application. The likely solution is to fit the push rod from the former unit if it is still to hand. Under the rubber boot is a circlip which, on removal, allows the push rod to be removed/replaced and this does not inolve interfering with any of the internals of MC. There is nothing exceptional here and some sellers make spefific mention of the fact that the push rods are 'generic' and may need to be adapted. In the event of previous rod not being available then adjustable push rods for Girling 0.625 units are widely available, but not that cheap. Cutting and rewelding can be done but, given the forces exerted, such welding should be of an exacting standard. Link to comment Share on other sites More sharing options...
DanMi Posted June 9 Report Share Posted June 9 (edited) If you can't find the old one the clutch MC pushrod is exactly the same, so you can compare against that. In fact the cylinders are basically the same though the brake one has a bigger reservoir the operating parts are identical (I use a clutch MC for the brake though smaller type 12 callipers) Edited June 9 by DanMi Link to comment Share on other sites More sharing options...
SpitfireGeorge Posted June 9 Report Share Posted June 9 Hi Guys, Finally sorted it. I extended the threaded portion of the pushrod by about 15mm. This allowed the bracket to line up with the brake pedal whilst the pushrod is fully out. The brakes now come fully off when my foot releases the pedal. Thanks guys for the help you have given. It is a great comfort to know you are there willing to help. Thanks again, Brett 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 9 Report Share Posted June 9 i recall on our Vit6 we slotted the bracket to baulkhead holes to give some adjustment you can change the pedal height with this adjustment , does need good washers fitting pleased the clues added up to a cheap fix ,always the best way Pete Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now