sgiitk

Thought CV joints? Caught: Guard Plate !

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My Santro AT has done about 38,000km. Of late I am getting a lot of vibrations and some noise in reverse. They are getting worse. Forward is perfectly Ok.

 I also had a small hole in the exhaust which was changed last Saturday.

I am suspecting worn CV joints as the cause. Since the car is totally used for town running, so in terms of wear it must me much more than a mixed mode 40k!

Any ideas?

sgiitk2010-06-18 14:49:38

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Vibration in the Reverse Gear are probably due to its Tall Gear-Ratio for Reverse gear & Slight more Throttle Input solves that problem.

But If they still persists, then look at the Engine Mounts(I'm considering CV as Constant Vibrating Joints, please correct me If I'm wrong for my Ignorance here), they'll definitely Show the signs of Wearing.

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@dr_nishu: Tall gear ratio in reverse, are you joking. The gear ratio has been the same since 2005!

CV Joints: Constant Velocity Joints. These are the ball joints between the gearbox output (incl diff) and the front wheels, to take care of the steering. Not found in rwd cars.

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Sir,

Are the tyres in good condition. As you are running the car only inside the town, might be the rubber has hardened & the CV joints are vibrating, but as you said there is no vibrations in forward, very intresting that to at 38k, CV joint vibrations. I am having a Wagon R which has run for more than 1 Lakh Kms, still not problems as such in the CV joints nor the suspensions.

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Strange problem. Its probably not the CV joints or tyres though. And the A.S.S is probably no good at diagnosing AT issues.

When was the last AT Fluid change ?dtandon2010-06-19 17:26:09

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Tall gear ratio in reverse' date=' are you joking. The gear ratio has been the same since 2005!
[/quote']

 

I'm not saying that way sir, but some cars demands slightly more Pedal Input while Reversing, but just with a difference of 19-20 only.

 

So, probable reason for your Query seems to be with Worn Engine mounts, but again for 38k mileage clocked yet, this also seems to be distant Issue.

But do get them checked before CV joints Inspection.

 

Have you Installed Alloy wheels on your Santro or not ??

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Folks. Please note the car has no problems in forward so I suspect either a transmission related problem, or could be, but unlikely the engine mounts, since the stresses will reverse to a certain extent. Why the CV joints are the first suspects, is because the wheel rotation is reversed. In my old Zen AT CV joints lasted only 40k or so. This car is totally local driving, so the wear and tear will be more.

I switched from the S322's to Turanza's about three months ago, while this problem has been there only for the past 3 weeks or so. Given the competence (or otherwise) of ASS I want to have a likely diagnosis in mind before going there.

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@sgiitk - Changing the engine mounts could be tried (should be easy on the pocket). What is the recommended AT fluid change interval - you haven't mentioned when it was changed last.

I'm not familiar with the santro - does it have a separate mount for the gearbox?

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Hey sgiitk, the easiest way to check for bad CV joints is to drive in a circle at full lock and hear for clicking noises. Do this in both forward and reverse. But I have a feeling this isn't the CV joint.

 

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@Dtandon: I think it is something like 80k! If it was the ATF then it should misbehave in both directions of locomotion.

@300kph: Thanks for the idea - will check it out.

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DrNishu,

 

Bearings when they go bad generally make humming noises. CV joints will click when driven through turns due to play. The clicking can come either on accelerating or decelerating. Test should be carried out in both left and right hand turns on full lock in forward and reverse while modulating the accelerator pedal.

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Seems to be rear brakes ultimately!

Today the car was baulking in reverse. Then all of a sudden there was a crack sound and the problem went away. On checking I found the left rear cylinder leaking as well as no hand brake. How did the two happen together I do not know. The Handbrake is not hydraulic! Now the sound in reversing is gone. I can clearly feel that one of the circuits in the dual circuit brakes has failed. I had to add about 150ml of brake fluid as we..

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I had some problem with my rear drums some years back. It happened during monsoon. I used to park my car with the handbrake on and if it rained the rear wheels locked. When the handbrake was released and only the front wheel rotated.

The treatment was to remove the wheels and hammer the rear drums until it was set free. The problem went away after one service, where they opened the rear drums and adjusted something.

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@sb-alto: if I lose brake oil, see oil marks on the drum and lose the handbrake then it is more than just a jammed drum. I find the lining often delaminates after 6-7 years but this is a shade under 5.

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There was no loss of brake oil as far as I remember, but the strange thing is that it happened only after a heavy spell of rain. All other season it remained fine. Even during monsoon if it did not rain on a day, the problem was not there.

Does brake oil moisture play a role here ?

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Moisture in the brake oil is not such a big culprit - though theoretically water can lead to corrosion. It should be changed every two years for two reasons - a. moisture can become steam under hard braking, and then it is like air in the hydraulics and you lose braking, and b. left for years the brake oil cam polymerise into a viscous fluid. If have seen this happen once.

What is likely to have been the problem in your case is corrosion in the adjuster mechanism, which led to the jamming.

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Got the car back yesterday, and behaving normally. Examined the dejecta membra. The pad on one shoe had delaminated. I have seen the glue giving way in 6-7 years, this is the first time I have seen it in just under 5 years.

I still do not understand why the handbrake failed!!

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Got the car back yesterday' date=' and behaving normally. [/quote']

 

That's Good sir !

You've easily got Rid of that trouble-

1stly: Very quickly &

2ndly: In a very Economical way.

How much that Minor Repair costed to you ??

 

this is the first time I have seen it in just under 5 years.
I still do not understand why the handbrake failed!!

 

May be due to Clutch-less AT, leading to Forced Rubbing of the Drum Brake Shoe while Braking, as In Manual people used to Depress the Clutch pedal while Braking(even if its not a Good practice) & letting its Wheel moving freely !! 

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May be due to Clutch-less AT' date=' leading to Forced Rubbing of the Drum Brake Shoe while Braking, as In Manual people used to Depress the Clutch pedal while Braking(even if its not a Good practice) & letting its Wheel moving freely !! 
[/quote']

AT has nothing to do with this. Yesterday I was with a very reputed parts & MM dealer. he said that sticking rear linings are a problem with Santro.

As for the practice of declutching when braking, it is highly dangerous, as is the Indian habit of either releasing teh clutch or lifting off the throttle when going round a bend. The only proper way of going round a bend is under power and accelerating.

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Finally caught

There was still a bit of noise left in reverse. We accidentally (pun intended) found the cause on Saturday. On Saturday when negotiating one of the potholes (Kanpur only has potholes and no roads), the front end bottomed. Now a noise akin to a holed silencer started. Went into a garage. They also thought it was an exhaust. Finding none they looked aroud and found that the plate which protects the gearbox was touching its bottom. So took it out, hammered out the indentation , and all is fine.

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Good to know that the problem is gone.

How come the sound came only in reverse? If it was a plate it should have produced noise even with forward motion. Must have been at an angle then.

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