Nick Jones Posted December 5, 2021 Report Share Posted December 5, 2021 Ah, missed that. Oops….. No personal experience of new type 14s but there was a thread (or maybe even a couple of them) on this forum, probably in this very section, involving similar sounding issues on type 14s. Not sure if there was a final outcome on those? Nick Link to comment Share on other sites More sharing options...
PeteH Posted December 6, 2021 Report Share Posted December 6, 2021 I think the "general conclusion " was that it`s maybe better to refurbish O/E ones than replace with repro`s. Mine are new on the 13/60, (came with the "kit of parts"). But seeing as it will be a (long?) while yet before it hits the road. I will just have to hope it s OK? Pete Link to comment Share on other sites More sharing options...
Chris A Posted December 6, 2021 Report Share Posted December 6, 2021 Same problem with the type 14s, as per the article I shared. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted December 6, 2021 Report Share Posted December 6, 2021 2 hours ago, PeteH said: But seeing as it will be a (long?) while yet before it hits the road. I will just have to hope it s OK? Pete You'll only find out when you try it on the road. My own 13/60 is terrible, a lot of pedal travel for what seems like little effort - it does stop and I suppose it did pass MOT - but I rebuilt the calipers, fitted new pads and discs and they may still be bedding in. I never liked brand new full-size pads, they always have to wear down a bit to allow more movement of the piston to get over that initial resistance from the rubber seals. It always seemed to me that the further the piston sits out of the caliper, the better they worked ie more fluid in behind. The handbrake is excellent so I'm blaming the fronts. One thing that is planned is the replacement of the master cylinder; it currently has a small cylinder with the disc brake extension tube but I'm going for one of the large plastic reservoir versions, and will at least see if that improves things any, since I'm unsure of the efficiency of the current cylinder. Link to comment Share on other sites More sharing options...
Josef Posted December 9, 2021 Report Share Posted December 9, 2021 On 05/12/2021 at 11:21, Pete Lewis said: the handbrake lever pivot pins can wear a groove in the back plate stops the cyl from sliding properly I've redone my Herald's rear brakes completely, rebuilt backplates with that groove built up with weld, new levers, clevis pins etc. It's no surprise how poor the handbrake was before with the amount of play from the wear to all those parts. Link to comment Share on other sites More sharing options...
Patrick Taylor Posted December 13, 2021 Author Report Share Posted December 13, 2021 It was drier in the garage than outdoors today, so I thought I'd have a look at the old calipers. One I knew was still working, and once the seals were off it was simple to remove the pistons. They have light staining on the pistons, no obvious wear, and I'm pretty certain a rub with a clean soft cloth will have them good as new; I already have a couple of seal kits so no further expense needed on that one. The seized caliper took a bit more work: I had to split the two halves to allow access, but eventually got both pistons out. They only have a step for the seal and not a groove and as a result are quite severely rusted. Both calipers had a grey sludge in them and will need cleaning out. The bores look to be fine. Given that I may rebuild both calipers and return the repro ones for refund, I need to know if all replacement pistons the same? Are any suppliers better than others? There's no point in rebuilding them if I end up in the same position... Link to comment Share on other sites More sharing options...
johny Posted December 13, 2021 Report Share Posted December 13, 2021 I take it then Patrick you have decided the problem is with the new calipers? Link to comment Share on other sites More sharing options...
Patrick Taylor Posted December 13, 2021 Author Report Share Posted December 13, 2021 2 hours ago, johny said: I take it then Patrick you have decided the problem is with the new calipers? I think so. I'll try removing the pads and applying the pedal as suggested here, but given I already have the seals and now 'only' need two new pistons, I have a Plan B if the new calipers don't settle down. I had hoped that replacement would be the easy option, but as @Colin Lindsay said many posts ago, a rebuild may be better. I trust myself to do a decent job but was a bit wary of something so critical to the safety of pedestrians, passengers, other drivers and me -in that order! If the repro calipers turn out to be OK then I will have gained a little experience for little outlay. Link to comment Share on other sites More sharing options...
johny Posted December 13, 2021 Report Share Posted December 13, 2021 So youre confident its not a problem with the rear brakes? One thing the manual recommends is clamping brake hoses to identify where a problem is. Obviously you would have to use something thats not going to damage them but perhaps you could do this on the rears to prove the problems at the front... Link to comment Share on other sites More sharing options...
Patrick Taylor Posted December 13, 2021 Author Report Share Posted December 13, 2021 The rears were working perfectly well before, so I have no reason to suspect them. I can't clamp off the hoses as they are braided stainless. I've bled so much fluid from the rears I would think any air that might have got in when the fronts were off will have been purged by now, too. The received wisdom seems to be that repro calipers can be suspect. If I recon the old ones then at least I'll have something to compare the repros to. Link to comment Share on other sites More sharing options...
johny Posted December 13, 2021 Report Share Posted December 13, 2021 Sounds reasonable. Although with the car stationary you could try the brakes with the handbrake fully on - the pedal will obviously harden up but after being left a while and tried again will have excessively travel if, as suspected, the the pistons have been pulled back too far... Link to comment Share on other sites More sharing options...
Colin Lindsay Posted December 14, 2021 Report Share Posted December 14, 2021 15 hours ago, Patrick Taylor said: I think so. I'll try removing the pads and applying the pedal as suggested here, but given I already have the seals and now 'only' need two new pistons, I have a Plan B if the new calipers don't settle down. I had hoped that replacement would be the easy option, but as @Colin Lindsay said many posts ago, a rebuild may be better. I trust myself to do a decent job but was a bit wary of something so critical to the safety of pedestrians, passengers, other drivers and me -in that order! If the repro calipers turn out to be OK then I will have gained a little experience for little outlay. I've just rebuilt another Herald type 14; far easier to work on the pistons and seals when the caliper is in two halves, especially if it requires light honing, but I still have never found a tightening torque for the two halves on reassembly. Just tighten as tight as you can without wrenching the bolt head off. Link to comment Share on other sites More sharing options...
Patrick Taylor Posted December 18, 2021 Author Report Share Posted December 18, 2021 Right: I finally got to tinker. The rear brakes were a few clicks out of adjustment and setting them correctly has improved matters considerably; it all feels much better. I hope to use the car more -she has been standing idle since the run to Stony Stratford on New Year's Day 2020- so here's hoping the Sarratt (Boxing Day) and Stony Stratford gatherings are back on...and the pads bed in! Link to comment Share on other sites More sharing options...
Colin Lindsay Posted December 18, 2021 Report Share Posted December 18, 2021 21 minutes ago, Patrick Taylor said: ...and the pads bed in! Let us know how much that improves things, it's always good to know. Link to comment Share on other sites More sharing options...
Joel Posted October 16, 2022 Report Share Posted October 16, 2022 Currently going through the same problem after caliper replacement - the pedal travel is much more pronounced than before. No air in the lines and pads sitting correctly. I shall give Nick's idea a go. Link to comment Share on other sites More sharing options...
Joel Posted November 12, 2022 Report Share Posted November 12, 2022 On 16/10/2022 at 12:10, Joel said: Currently going through the same problem after caliper replacement - the pedal travel is much more pronounced than before. No air in the lines and pads sitting correctly. I shall give Nick's idea a go. I still haven't found the issue but have narrowed it down to the servo unit (repalced three years ago) When I pump the brake pedal, the revs rise - is this normal? Din't do it before I changed the caliper. Link to comment Share on other sites More sharing options...
johny Posted November 12, 2022 Report Share Posted November 12, 2022 Well always each time you press and release the brake pedal the servo diaphragm goes back n forth so a quantity of air from the servo chamber is released through the vac connection to the inlet manifold and if done enough I would expect it to affect the revs. However if it does it as you slowly press the pedal then it could be the diaphragm is punctured and air is passing through it to the manifold... Link to comment Share on other sites More sharing options...
Peter Truman Posted November 12, 2022 Report Share Posted November 12, 2022 Isn't there a reflux/one way valve where the vac hose connects into the servo to stop this? Link to comment Share on other sites More sharing options...
johny Posted November 13, 2022 Report Share Posted November 13, 2022 There is but it works the opposite way - allows air to be sucked into the manifold from the servo but not the reverse. If it fails it means when the engine stops (most importantly if stalled) the servo loses its vac straight away so you have no residual assistance for one more braking... Link to comment Share on other sites More sharing options...
dougbgt6 Posted November 13, 2022 Report Share Posted November 13, 2022 The one-way valve in my servo is a simple rubber flap. it was not very efficient, and I had the symptoms mentioned here. I added an external one-way valve to the vacuum line which made the thing work as it should. Doug Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 13, 2022 Report Share Posted November 13, 2022 in general there should be around 5 applications of assisance with engine stalled before all the vac is exhausted when idling a push on the pedal lets air into the manifold and cause a short mixture but only when intially pressed if it lets air all the time as Jonny saya its a diaphragm problem or the small air valve piston has stuck check the filter and its associated small valves 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