harrytr5 Posted October 10, 2022 Report Share Posted October 10, 2022 Thanks Jon. I am relieved the part is made in Sweden And Scancar (Sweden) are saying it is not the servo and I am the only one this is happening to( where have I heard that a lot) seems to be a Standard line. Engine note rises when pressing on the pedal when stationary but still feels spongy when pressing hard. The brakes work well in action.I have used silicon for around thirty years and still using it but could this be the problem as the servo is a much more powerful item and showing up problems because of it. Just love our hobby and head scratching problems that tend to pop up. Some self inflicted of course. Regards Harry Quote Link to post Share on other sites
Rob Y Posted October 10, 2022 Report Share Posted October 10, 2022 Harry, I fitted the Scancar product and so far no issues so I’m following this with interest. I think Scancar are in Holland, not Sweden, but of course that doesn’t mean anything regarding where the parts are made. I had some issues ordering mine online and ended up speaking with them on the phone. It seems the part I had ordered wasn’t in stock, but they had another similar one in stock but it was more expensive. I said I was happy to wait for the cheaper one, but shortly afterwards I got an email to say my part had been dispatched. Could have been the more expensive one and if so what does that mean? I’m afraid I don’t have an answer, but it seems there might be different suppliers/quality out there…..even from the same supplier. I absolutely love this mod, so like you I hope I don’t have to go back to the old set up. Rob Quote Link to post Share on other sites
stuart Posted October 11, 2022 Report Share Posted October 11, 2022 14 hours ago, harrytr5 said: . Engine note rises when pressing on the pedal when stationary but still feels spongy when pressing hard. The brakes work well in action.I have used silicon for around thirty years and still using it but could this be the problem as the servo is a much more powerful item and showing up problems because of it. Just love our hobby and head scratching problems that tend to pop up. Some self inflicted of course. Regards Harry That is a possibility, try bleeding some fluid out and see if its a bit foamy. Is your master a TRW unit? Stuart. Quote Link to post Share on other sites
Waldi Posted October 11, 2022 Report Share Posted October 11, 2022 Hi Harry, I have the Volvo servo too, combined with SBF. My pedal felt a bit soft too, but now that everything has worn in and I did a second bleed action, it is good. The pedal never went to the floor, so I would start with more bleeding, as our Principal engineer above recommends. Cheers, Waldi Quote Link to post Share on other sites
stuart Posted October 11, 2022 Report Share Posted October 11, 2022 By the sounds of it Harry thats the same failure mode as we had a lot of years ago with the TRW masters though they never admitted there was a problem. Stuart. Quote Link to post Share on other sites
harrytr5 Posted October 11, 2022 Report Share Posted October 11, 2022 15 hours ago, Rob Y said: Harry, I fitted the Scancar product and so far no issues so I’m following this with interest. I think Scancar are in Holland, not Sweden, but of course that doesn’t mean anything regarding where the parts are made. I had some issues ordering mine online and ended up speaking with them on the phone. It seems the part I had ordered wasn’t in stock, but they had another similar one in stock but it was more expensive. I said I was happy to wait for the cheaper one, but shortly afterwards I got an email to say my part had been dispatched. Could have been the more expensive one and if so what does that mean? I’m afraid I don’t have an answer, but it seems there might be different suppliers/quality out there…..even from the same supplier. I absolutely love this mod, so like you I hope I don’t have to go back to the old set up. Rob Your right Rob Made in Holland and bought from Scandcar in Holland Regards Harry Quote Link to post Share on other sites
harrytr5 Posted October 11, 2022 Report Share Posted October 11, 2022 Thanks for the replies much appreciated. One Servo reconditioner suggested as I have four pot callipers the master cylinder is not man enough to work properly and that is your problem. They also said my servo is working properly. Confused or what? Now that could be the case or not. It is going to be something simple but what!. I can not remember where I bought the master cylinder from and I do have an original to send off for past parts to rebuild to discount that.As Stuart pointed out but I don't think it is a TRW one but it could be. I can not see the wood for the trees which is ironic being a carpenter all my life. Is there a specialist in braking out there who could test my car and say for definite it is this or that.Stuart is a tad too far from me but you never know! I have only had this problem on my own TR5 which is strange! Regards Harry Quote Link to post Share on other sites
FatJon Posted October 11, 2022 Author Report Share Posted October 11, 2022 1 hour ago, harrytr5 said: Thanks for the replies much appreciated. One Servo reconditioner suggested as I have four pot callipers the master cylinder is not man enough to work properly and that is your problem. They also said my servo is working properly. Confused or what? Now that could be the case or not. It is going to be something simple but what!. I can not remember where I bought the master cylinder from and I do have an original to send off for past parts to rebuild to discount that.As Stuart pointed out but I don't think it is a TRW one but it could be. I can not see the wood for the trees which is ironic being a carpenter all my life. Is there a specialist in braking out there who could test my car and say for definite it is this or that.Stuart is a tad too far from me but you never know! I have only had this problem on my own TR5 which is strange! Regards Harry Harry, I can only add that I too have AP 4 pot calipers on the front but no problems. My rears are new but standard cylinders and all my hoses are modern braided ones. The master cylinder is standard TR6 but I don't know what manufacturer or vintage it is. My best tip would be that if a caliper or slave cylinder is leaking you will see fluid, if the master cylinder is leaking the fluid goes around the seals and back to the reservoir so you see no leak. If it's neither of those possibilities it's air or a swelling hose. My order of work would be a close examination of all the calipers and slaves for signs of dampness, then replace master cylinder and a damn good bleed with a power bleeder. I did have quite a job getting all the air out. It would stop bubbling and all appear OK then when I went around again I found more air. I went around the car several times before things firmed up fully and I was happy with the pedal feel. Next step for me would be to look at changing flexible hoses. I'm not sure there is any brake expertise or technical equipment that will diagnose it in any more definitive way. It's a hydraulic circuit and if you go at it logically it will eventually give up its secret. I did have a problem on my MG Maetsro Turbo when I did a conversion to rear disks in which the master cylinder was not of sufficient capacity for disks all round and I ended up with a too long brake pedal travel but it still remained good and solid at the end of it's travel with no further sinking (I changed it for a bigger one regardless). Quote Link to post Share on other sites
harrytr5 Posted October 11, 2022 Report Share Posted October 11, 2022 44 minutes ago, FatJon said: Harry, I can only add that I too have AP 4 pot calipers on the front but no problems. My rears are new but standard cylinders and all my hoses are modern braided ones. The master cylinder is standard TR6 but I don't know what manufacturer or vintage it is. My best tip would be that if a caliper or slave cylinder is leaking you will see fluid, if the master cylinder is leaking the fluid goes around the seals and back to the reservoir so you see no leak. If it's neither of those possibilities it's air or a swelling hose. My order of work would be a close examination of all the calipers and slaves for signs of dampness, then replace master cylinder and a damn good bleed with a power bleeder. I did have quite a job getting all the air out. It would stop bubbling and all appear OK then when I went around again I found more air. I went around the car several times before things firmed up fully and I was happy with the pedal feel. Next step for me would be to look at changing flexible hoses. I'm not sure there is any brake expertise or technical equipment that will diagnose it in any more definitive way. It's a hydraulic circuit and if you go at it logically it will eventually give up its secret. I did have a problem on my MG Maetsro Turbo when I did a conversion to rear disks in which the master cylinder was not of sufficient capacity for disks all round and I ended up with a too long brake pedal travel but it still remained good and solid at the end of it's travel with no further sinking (I changed it for a bigger one regardless). Thanks Jon, Looking at my brake master cylinder it has Lucas embossed on it so I think it is a TRW one. I have just sent an original one to Past Parts for them to refurbish.They also said send the servo and they will test that for me. All good service I must say. I will re-look at all your suggestions and when i find it will let all know. The Volvo servo upgrade is so worthwhile despite my problems and I must thank you for that! Hope the electric windows went well (can send pics if you want to your email address) which I do not have. Regards Harry Quote Link to post Share on other sites
stuart Posted October 11, 2022 Report Share Posted October 11, 2022 FWIW Harry the symptoms you describe are exactly the same as the original TRW faults which were reckoned to be with the tipping valve so hopefully your reconditioned original should do the trick. Stuart. Quote Link to post Share on other sites
John L Posted October 11, 2022 Report Share Posted October 11, 2022 I had a long pedal travel some time ago and found that the front most valve was not sealing, so fluid was going back into the tank, the problem was the white plastic at holds the front seal which when the pedal is pressed it should seal fluid not going back to the reservoir, here's a picture of the white plastic part. You can see the plastic is holding off the rubber seal so will never seal properly, I did manage to get another plastic part but for now I don't remember where I got from. Why not take the 2 brake pipes off the master cylinder, and place caps in their place, then press on the master cylinder this will confirm if you have any leakage in that master cylinder. John Quote Link to post Share on other sites
PodOne Posted October 11, 2022 Report Share Posted October 11, 2022 From my limited past experience and as already said I’d bet it’s a master cylinder issue. I once had an issue where a MC seal had flipped and was letting fluid past and I could not get a firm pedal while driving the servo was making it worse. Not a bad idea to have the old OEM MC reconditioned and fitted. Keep us all posted Harry. Andy Quote Link to post Share on other sites
harrytr5 Posted October 13, 2022 Report Share Posted October 13, 2022 Well the post office managed to break my master cylinder (which is paradoxical) and compensation form is a joke! Lucky for me Past Parts had just one original left in stock and I paid the surcharge and will get it returned in three weeks. The master cylinder that I fitted twenty years ago is a TRW one and Past Parts will not recon it which tells its own story (think the bore is a different size so I am told). Will keep you posted and hopefully will sort it. Regards Harry Quote Link to post Share on other sites
harrytr5 Posted November 2, 2022 Report Share Posted November 2, 2022 Received my Past Parts rebuilt master cylinder today and soon fitted. Bled the brakes (first bleed) and solid pedal. Start the engine and exactly the same result, pedal can be pushed nearly to the floor so I can only deduce the servo does not hold the pressure. Before I take it off and send to Past Parts to test what else can it be. I am on silicon brake fluid but have not had this before I fitted the Volvo servo so it can only point to that surely! Regards Harry Quote Link to post Share on other sites
FatJon Posted November 2, 2022 Author Report Share Posted November 2, 2022 1 hour ago, harrytr5 said: Received my Past Parts rebuilt master cylinder today and soon fitted. Bled the brakes (first bleed) and solid pedal. Start the engine and exactly the same result, pedal can be pushed nearly to the floor so I can only deduce the servo does not hold the pressure. Before I take it off and send to Past Parts to test what else can it be. I am on silicon brake fluid but have not had this before I fitted the Volvo servo so it can only point to that surely! Regards Harry Harry, the servo has no part in the hydraulic pressure of the brake system. If you take it apart you will see nothing but a solid metal rod (ok, maybe a ball and cup joint) between the brake pedal and the master cylinder piston. There is nothing to go wrong in there other than a diaphragm failure which would leave you with working but unassisted brakes. By its nature a servo is fail safe. The fact that the pedal is hard until the engine creates vacuum tells you the servo is fine as that is exactly what should happen. The pedal should be very hard and sink a little under very light pressure as the engine starts. Look at flexible hoses next. The fluid leaving the MC is going somewhere and if it’s not a puddle under the car then something is “giving” under the considerable extra pressure. There are several possibilities, a soft hose or weak drum or air spring first to mind now the MC is out of the equation. Tomorrow I will measure my pedal height with engine off and under very hard pressure with engine running so you have some comparison data. That should at least show up any major differences in the way we installed it if they exist. Quote Link to post Share on other sites
Waldi Posted November 2, 2022 Report Share Posted November 2, 2022 Hi Harry, John (above) may have a very good point. I have the same servo, and yes, it moves further down when you press on the pedal and then start the car. I have SBF too. In my case it improved after another venting-excercize after a couple of weeks, maybe small air bubbles had “joined” to form bigger bubbles which are easier to remove (I do not know the correct english word/terminology)? Also, the new shoes/pads are now properly bedded in, which reduced the large travel further. Waldi Quote Link to post Share on other sites
charlie74 Posted November 2, 2022 Report Share Posted November 2, 2022 Silicon brake fluid entrains small bubbles which will result in a soft pedal. When I converted mine the pedal feel improved quite a bit after a few days… Quote Link to post Share on other sites
Mk2 Chopper Posted November 3, 2022 Report Share Posted November 3, 2022 Are you sure there is enough clearance between the servo push rod and the mc? A bit of a pain but can you go back to the original servo to test, this would confirm the mc's are OK, and that it's something to do with the fit of the servo. Gareth Quote Link to post Share on other sites
harrytr5 Posted December 6, 2022 Report Share Posted December 6, 2022 Well after going round and round adjusting this and that. Bench bleeding the master cylinder, bleeding the brakes. Getting a solid brake with engine off. Engine on I can still push the brake down to nearly the floor (this is when stationary) works well when driving and stops the TR very well. When stationary, engine on and pressing the brake pedal down I can hear air escaping. The supplier of the servo Scandcar in Holland has asked me to send it back for testing and a replacement. Now this exercise is getting expensive as postage is £50 to send back which I have and they should have this week. If they find nothing wrong with the servo I am bandaxed and back to original servo. Having done this conversion I do not want to go back to standard but may have to. Ain't our hobby grand Regards Harry Quote Link to post Share on other sites
harrytr5 Posted December 7, 2022 Report Share Posted December 7, 2022 For you guys that have done this can you tell me when stationary, engine running then press on the brake pedal can you hear air escaping. If you can not then that is my problem. The atmosphere side of the chamber maybe leaking or the vacuum side letting by. The servo will be looked at by the suppliers in the next few days and just hope it was faulty and not an expensive mistake! Regards Harry Quote Link to post Share on other sites
Rob Y Posted December 7, 2022 Report Share Posted December 7, 2022 Hi Harry, I have done this mod, also supplied from Scandcar in Holland, so I’ve been following your comments with interest. I have not heard any air escaping when using the brakes as you have said. I do have a long brake pedal movement when I first use the brakes but this was the case with the old servo and has been the topic of another posting, so nothing like you’ve mentioned. Like you, I absolutely love this mod, so I hope it continues to work well. I also hope you can solve this with a replacement servo. Fingers crossed. Regards Rob Quote Link to post Share on other sites
harrytr5 Posted December 7, 2022 Report Share Posted December 7, 2022 Thanks Rob, Just hope it is the servo! Regards Harry Quote Link to post Share on other sites
harrytr5 Posted December 15, 2022 Report Share Posted December 15, 2022 Just waiting for custom clearance in Holland to release the servo back to Skandcar to test. Hope it is indeed faulty or an expensive waist of time and money if not. Hey Ho, Regards Harry Quote Link to post Share on other sites
FatJon Posted December 16, 2022 Author Report Share Posted December 16, 2022 There is no possible fault on a servo that causes the pedal to sink to the floor. A hard pedal or no assistance are possible but this symptom, no possible way. Quote Link to post Share on other sites
harrytr5 Posted December 16, 2022 Report Share Posted December 16, 2022 You are probably right Jon and I will have to cut my losses and go back to standard if the servo turns out to not be the problem. Shame as the conversion did work so well..... Regards Harry Quote Link to post Share on other sites
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