Buddsy 1,469 1 Vehicles Report post Posted August 13, 2018 @ChrisJ suggested we split @Sparky's thread "85TE Checkover" as the thread has developed into a brake upgrade discussion around the idea of improving the vacuum system. I will move the relevant posts here. On 13/08/2018 at 21:20, Sparky said: Brakes not great (they rarely are on these) - check vacuum/servo/non-return valve, just in case. I had mine 85 in for MOT on Friday. First time ive driven for a couple of months and had a brown trouser moment driving along a the new NDR duel carriageway on the out skirts of noriwch. Hit the roundabout at about 70 and had very little braking going on. I wasnt sure if it was due to being used to my daily or if something had failed. Seemed a bit better and surprisingly passed the MOT with on an advisory to change the fuel lines (which I had been aware/monitoring) When I got home the brakes done the same thing. They are rock solid and not spongy but didnt seem to be doing much. Would this be an issue with the servo? Or something else? Maybe the pads need a bit of use? buddsy Quote "Belief is the enemy of knowing" - Crrow777 Share this post Link to post Share on other sites
Barrykearley 5,760 Report post Posted August 13, 2018 Pull the vac pipe off the servo and measure the vacuum level. then pull the non return valve off the servo and check again. 2 Quote Only here once Share this post Link to post Share on other sites
TAR 349 Report post Posted August 13, 2018 32 minutes ago, Buddsy said: They are rock solid and not spongy but didnt seem to be doing much. Would this be an issue with the servo? You can check the servo is working by pushing on the brake pedal with the engine off. Then whilst still pressing, start the car, the pedal should move down as the servo assistance kicks in. If it doesn't you'll have a faulty servo or no vacuum to it. 2 Quote It's getting there...... Share this post Link to post Share on other sites
ChrisJ 1,155 2 Vehicles Report post Posted August 15, 2018 On 13/08/2018 at 22:20, Sparky said: I may have overdone it with the photos! Impossible. @top-plumber has some interesting thoughts on the brakes and has a potential mod to improve them. Quote Share this post Link to post Share on other sites
Sparky 2,303 Report post Posted August 15, 2018 Cheers Chris. Wayne? Quote British Ambassador to Florida, New York, Denmark and Newfoundland. And Sweden. Share this post Link to post Share on other sites
top-plumber 521 Report post Posted August 15, 2018 10 hours ago, Sparky said: Cheers Chris. Wayne? Hey Gary, I had a thought that might be something. The vacuum on these cars is pulled via a very small tapped in connector on the intake manifold and stored in the reservoir on top of the right hand tank. I’m going to install an electric vac pump as on the S4 to operate the servo and let the reservoir serve just the dash. I put all the poor performance of the brakes down to not enough vacuum. Just a thought. I will let you know when my car is done. Although you may need an answer sooner so perhaps you could let me know how it works out. Quote Suspension, brakes, chipped, chargecooler rad and pump,injectors,ignition coils and leads, BOV, highflow cat and zorst, Translator and tie rods, Head lights, LEDs to tail lights and interior,Polybushes to entire front end, Rad fans, rad grill, front end refurb with aluminium spreaderplates and galvanised bolts. Ram air, uprated fuel pump, silicone hoses through out, wheels refurbed and powder coated,much more, all maintenance. Share this post Link to post Share on other sites
Sparky 2,303 Report post Posted August 15, 2018 That's exactly what I had been thinking! The pumps used for Ian's DM deletion would be ideal. And I agree: it's a vacuum issue. First pump in a TE is pretty good, but then you've exhausted the reserve and subsequent pumps are really wooden. Trouble is, for a G car, you'd be straying from original and I'm not sure many would go for it. We'll see... Quote British Ambassador to Florida, New York, Denmark and Newfoundland. And Sweden. Share this post Link to post Share on other sites
Barrykearley 5,760 Report post Posted August 15, 2018 What’s the vacuum level at the servo??? Quote Only here once Share this post Link to post Share on other sites
ChrisJ 1,155 2 Vehicles Report post Posted August 15, 2018 @Sparky - the brakes are the one area I'd move away from original, as the original are and always have been fairly shocking. I'm waiting on Wayne's results before I go for one of the bigger brake solutions. Quote Share this post Link to post Share on other sites
Sparky 2,303 Report post Posted August 15, 2018 @ChrisJ, I can understand that. I've done a few brake upgrades on G cars, and they're pretty disappointing. The work would be pretty much identical to the conversion on an SE High Wing. That being the case, I already know exactly what parts are required to make TE brakes good! @top-plumber we must chat about this... @Barrykearleyit's not the level of vacuum (which is fairly crap anyway); it's the fact that it can't be sustained by a turbo engine. Quote British Ambassador to Florida, New York, Denmark and Newfoundland. And Sweden. Share this post Link to post Share on other sites
Buddsy 1,469 1 Vehicles Report post Posted August 15, 2018 @ChrisJ Simon Freebery has AP racing brakes on his fronts. I dont think they had the biggest or most pistons but I think the performance was good on those items. buddsy Quote "Belief is the enemy of knowing" - Crrow777 Share this post Link to post Share on other sites
Barrykearley 5,760 Report post Posted August 15, 2018 30 minutes ago, Sparky said: @Barrykearleyit's not the level of vacuum (which is fairly crap anyway); it's the fact that it can't be sustained by a turbo engine. No mechanical vacuum pump then? Precisely why I haven’t connected the vacuum pipe to my S4s manifold....... Quote Only here once Share this post Link to post Share on other sites
910Esprit 431 1 Vehicles Report post Posted August 15, 2018 Vacuum is created between the throttle plates and the pistons/intake valves, which are always isolated from the turbo under braking (as throttles closed). Under braking the only difference to the vacuum, between an N/A and Turbo, would be created by the physical design of the engine (valve timing/compression etc). So the lower state of tune of the turbo engine will generate a little less vacuum (counteracted by Lotus fitting a larger servo). Independent contemporary road tests achieved 1g of retardardation (solid disc models) and recorded virtually no fade under stress testing. Some cars still seem to retain that performance, many do not. I wonder why? Quote Share this post Link to post Share on other sites
top-plumber 521 Report post Posted August 15, 2018 2 hours ago, Sparky said: That's exactly what I had been thinking! The pumps used for Ian's DM deletion would be ideal. And I agree: it's a vacuum issue. First pump in a TE is pretty good, but then you've exhausted the reserve and subsequent pumps are really wooden. Trouble is, for a G car, you'd be straying from original and I'm not sure many would go for it. We'll see... There is an electric vacuum pump from an S4s on eBay atm. Might be a bit small as they had the poxy ABS and pressure pump moraine system. There for the pump only ran the dash. If it didn’t make me physically sick I might consider the Audi electric pump. Mean while here is my sexy gearbox... 7 Quote Suspension, brakes, chipped, chargecooler rad and pump,injectors,ignition coils and leads, BOV, highflow cat and zorst, Translator and tie rods, Head lights, LEDs to tail lights and interior,Polybushes to entire front end, Rad fans, rad grill, front end refurb with aluminium spreaderplates and galvanised bolts. Ram air, uprated fuel pump, silicone hoses through out, wheels refurbed and powder coated,much more, all maintenance. Share this post Link to post Share on other sites
Sparky 2,303 Report post Posted August 15, 2018 Noooo, not Ooodi! That S4s pump really isn't up to the job. Around 20 inches of vacuum would be nice. 1 Quote British Ambassador to Florida, New York, Denmark and Newfoundland. And Sweden. Share this post Link to post Share on other sites
Barrykearley 5,760 Report post Posted August 15, 2018 S4s vac pump @top-plumber??? Not seen that one. The mechanical vac pumps give 19” consistently Quote Only here once Share this post Link to post Share on other sites
top-plumber 521 Report post Posted August 15, 2018 1 minute ago, Barrykearley said: S4s vac pump @top-plumber??? Not seen that one. The mechanical vac pumps give 19” consistently So where did you manage to fit that on the S4s. Ditch the a/c? Quote Suspension, brakes, chipped, chargecooler rad and pump,injectors,ignition coils and leads, BOV, highflow cat and zorst, Translator and tie rods, Head lights, LEDs to tail lights and interior,Polybushes to entire front end, Rad fans, rad grill, front end refurb with aluminium spreaderplates and galvanised bolts. Ram air, uprated fuel pump, silicone hoses through out, wheels refurbed and powder coated,much more, all maintenance. Share this post Link to post Share on other sites
Barrykearley 5,760 Report post Posted August 15, 2018 No chap - fitted an electric vac pump Quote Only here once Share this post Link to post Share on other sites
johnpwalsh 1,281 4 Vehicles Report post Posted August 15, 2018 15 minutes ago, Barrykearley said: No chap - fitted an electric vac pump Like a breast pump for a bigger suck. 2 Quote Share this post Link to post Share on other sites
davevr6car 34 Report post Posted August 16, 2018 I ditched the ac on my S4s and fitted a mechanical pump and it works a treat. Quote Share this post Link to post Share on other sites
Sparky 2,303 Report post Posted August 16, 2018 28 minutes ago, davevr6car said: I ditched the ac on my S4s and fitted a mechanical pump and it works a treat. Why? Did you change to a servo brake system? Quote British Ambassador to Florida, New York, Denmark and Newfoundland. And Sweden. Share this post Link to post Share on other sites
jonwat 290 Report post Posted August 16, 2018 11 hours ago, 910Esprit said: Vacuum is created between the throttle plates and the pistons/intake valves, which are always isolated from the turbo under braking (as throttles closed). I agree with this statement, except where the driver is heel & toeing, so could someone explain why all petrol turbo cars have mechanical or electrical vacuum pumps for the brake servo rather than relying on the manifold vacuum? Sorry if the post is off topic. 1 Quote Cheers, John W http://jonwatkins.co.uk Share this post Link to post Share on other sites
Barrykearley 5,760 Report post Posted August 16, 2018 Turbo cars are forced induction. Hence little or no vacuum. Quote Only here once Share this post Link to post Share on other sites
jonwat 290 Report post Posted August 16, 2018 15 minutes ago, Barrykearley said: Turbo cars are forced induction. Hence little or no vacuum. As 910Esprit stated the vacuum is created between the throttle & the piston when the throttle is closed irrespective of whether the turbo is creating boost or not & even if it is creating boost there's a valve between the intake take off & the servo which would prevent the servo being pressurised. 1 Quote Cheers, John W http://jonwatkins.co.uk Share this post Link to post Share on other sites
Barrykearley 5,760 Report post Posted August 16, 2018 Measure the static vacuum - that will show you how little there is Quote Only here once Share this post Link to post Share on other sites
