Rear brakes soft

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kaarel
Posts: 70
Joined: 31 Jul 2008 10:03 am
Location: Tallinn

Rear brakes soft

Post by kaarel » 28 Dec 2020 09:53 am

With search could´t find info so making new topic:D

In spring, on every year inspection my 340 cvt failed rear brake test 3 times. Issue is that foot brake is working but weak. on 4th time passed test,but it was like okey old volvo let it be.
(They calculate rear axel mass and wheel resistance during braking or something like that.)
Front axel as it should.
Handbrake good and better than rear axel foot brake. They say rear brakes do not have enough power.

Usually I have problems with handbrake,never with foot brake. :D

I have cleaned, done bleeding. open up the rear cylinders, done bleeding again.-nothing
in autumn before car went into garage, did test again still nothing. Drove about 2000 km during summer, so standing/ low usage is not involved.

1.Can this be the brake power distributor? https://www.volvo340onderdelen.nl/en/vo ... d=93033317

2. Don´t think that drums are worn, otherwise handbrake would be the issue as well.

Has somebody faced the b.p distributor issue? at least no topic in internet :D I know that on 200 series they start leaking and that´s why they will be cut out.


thanks and wash hands :D
Kaarel

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bogbasic
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Location: New Malden, Surrey.
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Re: Rear brakes soft

Post by bogbasic » 28 Dec 2020 10:13 pm

The first thing I would blame is the hand brake lever which goes through the back plate of the rear wheels. It has a pivot in it which always seizes and this messes up any adjustments.

Image.
1988 340 1.4 GL, 218k, 5 door (Grey Bess). Gone to CBA.
1991 340 1.7 GL, 64k, 5 door, petrol blue (Deep Blue).
1988 360 2.0 GLE, 140k, 5 door, ocean blue metallic (Blue Bess).
1989 340 1.7 GL, 108k, 3 door (Red Ness).
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kaarel
Posts: 70
Joined: 31 Jul 2008 10:03 am
Location: Tallinn

Re: Rear brakes soft

Post by kaarel » 30 Dec 2020 02:32 pm

Yes, have being fighting with that lever. Moved b.shoes and cleaned it, was moving as should.

My thoughts:

1. Try another brake stand, maybe something off with this companies one...
2. 2 years ago brake hose was replaced and new fluid was put in. Maybe new fluid flushed some dirt to brake power disp.?

Kaarel

Ride_on
Posts: 2259
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: Rear brakes soft

Post by Ride_on » 22 Mar 2021 10:44 pm

The bias valve (power distributor) should fail with more brakes not less (which can cause dangerous rear locking), mine had siezed with rust after sitting for 15 yrs. Just replaced with a more recently used unit from a car someone was breaking. I don't know if they can fail weak.

I've also had a gummed up lever, had to work alot of WD40 through it before it moved freely.

Trying having someone brake gently with the back wheels off the ground, while you try and turn the wheel by hand or maybe with the engine. Should give you some idea.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

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