| Author | Message | ||
     Bob Reynolds Experienced User Username: bobreynolds Post Number: 27 Registered: 8-2012 |
Two questions which may seem obvious to some, but I have heard conflicting information and I would like to get the official RR drivers' version! In a Silver Shadow (RHD) the parking brake is under the dashboard and rather tricky and inconvenient to operate whilst driving in traffic, as it is out of reach. Am I correct to assume that this is just meant to be a parking brake and not intended for use while driving (unless in a traffic jam, or similar long wait). Following on from this, is the car meant to hold itself on a hill without rolling back and without use of the parking brake? What is the official RR technique for hill starts? Use the parking brake, the left foot to brake (which we were taught NEVER to do), or adjust the engine/transmission so that it never rolls back? My present Silver Shadow doesn't roll back in general, but it will roll back slowly on a fairly steep hill. Enough to cause slight embarrassment to me, and mild panic to the driver behind! I was wondering if this is normal, and how it should properly be prevented. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2757 Registered: 4-2003 |
I know that many will ridicule me, but I never use the parking brake in any car with automatic transmission, and that includes a car like yours. I may add that this includes a million kilometers in Crewe cars. I do apply it and release it about monthly in each case just so that it keeps fat-free, and of course at roadworthiness tests, but that's it ! Fortunately my Conti R has the automatic parking brake release: move from Park or from Neutral and it releases automatically. That is good for valet parking as the operators can usually manage to apply but seldom know how to release the parking brake on any postwar Crewe car. Especially on SY and SZ cars, the parking brake is ruined within less than a kilometer of driving when left applied. RT. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2759 Registered: 4-2003 |
ps: left foot braking is de-rigueur for me and for most I know when driving a vehicle with two-pedal automatic transmission. For anyone, it is a great advantage for quick stops on a car with auto transmission even if you prefer right-foot braking for planned slowing. It shortens the reaction time by as much as half a second. By contrast, with conventional manual transmissions you need to swap both feet to activate When In Doubt, Both Feet Out. Mind you, you can shorten reaction times on a manual vehicle using the standard heel-and-toe method. RT. | ||
| Neville Davies Experienced User Username: nev_davies Post Number: 48 Registered: 9-2006 |
Bob. Like Richard I have always used my left foot for braking when driving automatics.I find it quite comfortable allows quicker reaction and I have never had a problem when reverting back to manual cars.A word of warning though, some of the modern cars require the foot brake to be completely released to allow acceleration our Passat being one so care is needed especially when joining a line of traffic where instant response is required. Nev | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2761 Registered: 4-2003 |
Neville, agreed. When I sat my driving test on my 17th birthday, a 0.08% blood alcohol level was allowed for learner drivers, cavorting with druids was a capital offence, you needed to go through border controls between France and Germany, and driving examiners fainted at left-foot braking. Apartheid was going strong, nuclear war seemed inevitable in Central Europe, ABBA was banned from Queensland and the world was quite different. I sat my test in a V8 car with manual transmission to avoid a licence restricted to automatic vehicles only. Nowadays society is generally far more sensible, and considered legislation has prevailed: you cannot drive a V8 in this country until you have held a full licence for a few years, you will lose it for any alcohol reading whatsoever during that period, texting while driving is a serious offence.... yet guns are encouraged in schools by the lobbies in the USA. Some way to go with the latter, but leave my left foot alone. RT. | ||
| Jeffrey McCarthy Grand Master Username: jefmac2003 Post Number: 376 Registered: 5-2007 |
I was always a bit disturbed about this tendency to roll backwards even on fairly slight slopes. I just got used to using left foot breaking. When I had the transmission rebuilt the problem did however decrease to a very noticable degree. It still happens a little but nowhere near as much as it used to. Could there be a relationship between the state of the gearbox and the tendency to roll in reverse while the engine is in drive? | ||
| Jan Forrest Grand Master Username: got_one Post Number: 443 Registered: 1-2008 |
My Shadow 1 is far from my first automatic car and I've yet to have one that couldn't hold position on the torque convertor at idle on quite steep slopes. It's puzzling that some can't even among the same make/models although there could be a correlation between slippage and ATF condition or level. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2763 Registered: 4-2003 |
Jeff, The short answer is No. If the condition of the transmission affects its hold-drag-creep characteristics it will be burned up in kilometres as the only real cause could be slippage in the one-way roller clutches often referred to as sprags (not many TH400s use sprags as standard, but the term is often shared with rollers). The main contributor to those is idle speed of course, and a very slight change makes a large difference. Assuming that the fluid is not aerating due to a low level or otherwise, the creep characteristics are determined by the torque converter – and maybe the fluid used (see below). The newly-overhauled 4L80E in my Conti R (same transmission as your 3L80 – TH400 but with overdrive, TCC and electronic control) behaves quite differently now although beforehand it was working fine too apart from the weak TCC. It may be a benefit of the synthetic fluid now in the system. This is the Atlantic brand fluid "Atlantic New Generation Automatic Transmission Fluid" to Dexron III specs as required for TH400 and 4l80E transmissions. Now the converter allows more slip than beforehand until the TCC engages and there is no slip. On upshifts the engine RPM stays higher than beforehand, although the computer has recorded no ratio errors so there can surely be no clutch slippage. Shifts are astonishingly smooth, almost imperceptible, even on full-throttle. I am assuming, and hoping, that all is OK, but I must say that it is nicer to drive albeit different from beforehand. I’ll call the converter repairers in Melbourne to see what they did, but I suspect that the fluid change is the reason. I did experience a similar but less pronounced change in converter performance on my Turbo R’s TH400 when I overhauled it and converted to synthetic, and it has not suffered over tens of thousands of kilometres. RT. | ||
| James Feller Prolific User Username: james_feller Post Number: 265 Registered: 5-2008 |
cannot help myself and am compelled to make a point on this thread....it maybe due to my size 11 feet.... I never ever needed to use my right foot to brake in an automatic car no matter the make, model or AT condition. Certainly as RT says the very low idle speed RPM;s in our cars about, 500rpm while in D, does not 'charge the convertor enough' to 'hold' the great weight of our cars on a medium to steep hill to negate a small amount of rollback when pulling away. I was taught and told, never use my right foot on AT cars to brake. I have of course used both feet on a few 'emergency' breaking manouvers in my driving history but that was more to do with maximum force, a bit of panic and needing to hit the STOP pedal QUICK to avoid whatever idiot or thing that had put itself infront of me... It's not necessary in any auto car, let alone Crewe cars to use your right foot for anything other than applying the parkbrake. Now unless some people have an issue with their ankles....the distance between the accelorator and brake is not that far, and unless a hill or incline thats being discussed above is of Mont Blanc steepness then I fail to see why anyones right foot rotating at the ankle in a 10' arc cannot suffice??? it takes not more than a fraction of a millisecond to rotate ones ankle right to left and left to right to drive a car... it seems very unnatural for me to even contemplate driving and auto with two feet. As for the parkbrake actually holding the car on a hill when stopped, this is where I don't agree with our GrandMaster and his practice of not using the parkbrake. My Crewe cars park brakes yes do hold the cars weight and stop them resting on the parking prawl. I've never liked the weight of the cars resting on the P gear alone. Instead, I have always, if parking on a hill applied Parkbrake first, released foot brake, the park brake then takes most if not all the weight and I apply P for locking and safety. If adjusted correctly and tight, the rear parkbrake should hold the cars fine on a hill. RT does have a very good point in that valets or anyone not familiar with the cars can get in and inadvertantly drive them with the park break on and ruin them in no time, 90MY cars and on sorted this irritation though with the nice to have autorelease system. J | ||
| James Feller Prolific User Username: james_feller Post Number: 266 Registered: 5-2008 |
eeeekkkk sorry, left left left ive got my lefts and rights mixed up. I meant of course the left foot is not needed....wow thats embarrasing.   | ||
| Jan Forrest Grand Master Username: got_one Post Number: 444 Registered: 1-2008 |
I've not had the Shadow on the road for over a year due to the very bad weather preventing me from doing virtually any of the work I wanted to carry out. Hopefully this will change as Spring (or the UK version of it) arrives. However there are a couple of steep hills that I have to use locally and none of my automatic cars - even the Rolls - have failed to hold position just on the gearbox. Although I almost never use the handbrake since it just makes the cable stretch I will take on board the advice about the parking pawl and start to use it while out & about if I have to park her on any kind of slope. | ||
| Martin Cutler Prolific User Username: martin_cutler Post Number: 193 Registered: 7-2007 |
I'm a left foot braker as well, even in my manual cars. Mk vi Bentley will roll back on a hill as servo effect stops, so hand brake very time I stop on a slope. Mg magnette is left foot brake and clutch less gear changes once you are under way. Bikes get confusing, left and right foot change, so rear brake is on different sides, makes it important to remember to brake not change gears, can get nasty. Cheers Marty |
