Resonance sound come from the roof

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Dumindu
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My tercel:: 1987 Toyota tercle 4wd DX Wagon 1452CC
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Resonance sound come from the roof

Post by Dumindu » Fri Apr 05, 2019 10:19 pm

My car is a Toyota Tercel 1987 4WD 1452CC DX Wagon.

Recently car roof has been repaired with adding a headlining cover sheet (pasted over the roof cover). All the connections were made properly per my knowledge. But the silencer pads which were pools of dust were removed and didnt replaced.

Now after the repair, when the car rear tires goes over a pit on the road, there is a resonance sound come from the roof. Now car is like a old lorry with custom made body (resonance sound).

Now I have to rebuild the roof cover again. Before I do that its better to get a professional advice.

What would be the cause for that sound?

Whether would this be due to lack of silencer pads or can be due to bad shock absorbers?
Last edited by Dumindu on Sat Apr 06, 2019 10:12 am, edited 1 time in total.

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Mattel
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My tercel:: 1988 Corolla 4wd Wagon (AKA Corolla All-trac) 5speed, AC, Power Sunroof, Windows, Mirrors, Steering, Locking, Diff Lock, 14" Corolla SX Alloys with Silica Hankook Tyres, 4afe, King Springs, Upgraded Headlights, Full Synth oils, 210,000kms
Location: Melbourne, Australia

Re: Resonance sound come from the roof

Post by Mattel » Sat Apr 06, 2019 1:39 am

Hi Dumindu, do you mean the interior roof lining of the roof? New shock asorbers could be good. Have you tried bouncing up and down on your rear bumper - jumping off and seeing how long it takes to settle to the right level? if only one or two bounces it should be ok but if it keeps bouncing it might be bad. Also is there leaks along side of the asorbers there might be an issue. You can change over with many different type of shock. just look for around the same length and fittings. I had some from a Mazda 626 that fitted.
Previous: 83 Tercel SR5 4wd, 84 Tercel SR5 4wd
88 Corolla 4wd Wagon 5speed, All power options, Fact Sunroof, Diff Lock, 14" SX Alloys, Hankook Tyres, 4afe, King Springs, Upgraded Headlights, Full Synth oils, Tow Bar, 210,000kms

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Petros
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Re: Resonance sound come from the roof

Post by Petros » Sat Apr 06, 2019 10:35 pm

the roof wants to "oil can", I think that dampening pad prevented this. I also think if you use some kind of adhesive between the roof and head liner it would dampen the drumming effect.

I would use something mildly sticky so you can pull it off if necessary without damaging the head liner, rubber cement is good for this, or some kind of latex caulk perhaps. likely you can also replace the missing insulation with something similar, like thin rubber floor mat material. but use rubber cement (not contact cement) to hold it in place, and than replace the head liner over it.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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Mattel
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My tercel:: 1988 Corolla 4wd Wagon (AKA Corolla All-trac) 5speed, AC, Power Sunroof, Windows, Mirrors, Steering, Locking, Diff Lock, 14" Corolla SX Alloys with Silica Hankook Tyres, 4afe, King Springs, Upgraded Headlights, Full Synth oils, 210,000kms
Location: Melbourne, Australia

Re: Resonance sound come from the roof

Post by Mattel » Sun Apr 07, 2019 6:37 am

Image There are these small pads that are used in many metal sided vans that I think Petros is talking about. http://diycamperconversion.com/soundpro ... amper-van/. As you can see you don't have to cover the whole roof to get a result.
Previous: 83 Tercel SR5 4wd, 84 Tercel SR5 4wd
88 Corolla 4wd Wagon 5speed, All power options, Fact Sunroof, Diff Lock, 14" SX Alloys, Hankook Tyres, 4afe, King Springs, Upgraded Headlights, Full Synth oils, Tow Bar, 210,000kms

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Dumindu
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My tercel:: 1987 Toyota tercle 4wd DX Wagon 1452CC
Location: Sri Lanka
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Re: Resonance sound come from the roof

Post by Dumindu » Sun Apr 07, 2019 11:12 pm

Thank you all for your valuable advises.

As Mr. Mattel suggested, I had tested shock-absorbers. After depress and release the rear bumper (Edit:)several times, there is one moderately large bounce and following few very tiny (vibration like) bouncing. Would that suggest shock-absorbers are ok?

As Mr. Petros advised, I will replace silencer pads. Same type of cusions found on the local market. There is a gum layer of the removed pads still remaining. I didnt scratched it since it will damage the paint. So may I paste rubber cement over the remaining layer?

I already had put oil to the roof when repairing.( Egnine oil 75% + Kerosine 25%)
Last edited by Dumindu on Tue Apr 09, 2019 6:13 pm, edited 1 time in total.

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Petros
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Re: Resonance sound come from the roof

Post by Petros » Mon Apr 08, 2019 6:26 pm

if it is well bonded, I do not see why you can not stick it to what is still on the roof.

the "old' shock test is to bounce the car up and down, it should dampen out in less than one cycle. if it cycles more than once, you need new dampeners.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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