The Montgomery County Commission on Lanlord-Tenant Affairs, under heavy pressure from a tenant's association, has voted to rescind a decision it made last month that would have opened the way for a special rent increase in a Silver Spring apartment building.

The vote Tuesday concerned a Montgomery County judge's ruling last year. That ruling had upheld a 1974 commission vote opposing any rent increase at the apartment.

But in December the commission in effect reversed its earlier 1974 position opposing the rent increase and asked the judge to reconsider his ruling. Tuesday's commission vote rescinded that December action ending the posibility that the judge would reconsider.

Tuesday night's vote after an unusual closed-door session apparently halts the commission's attempt to involve itself further in the two-year-old dispute between the Colesville Towers Tenants Association and Lawrence N. Brnadt, Inc., landlord of the 11-story apartment building at 8811 Colesville Rd.

Five members voted for the motion, two abstained, and two declined to vote.

In December, at the urging of Tom Hamilton, executive director of the Office of Landlord-Tenant Affairs, the commission voted to ask Montgomery County Judge Richard B. Latham to review his June, 1976, ruling, which upheld the commission's original rejection of Brandt's request for rent increases averaging 7 per cent at the building.

A special three-judge panel of the Montgomery County Circuit Court in late December upheld Latham's ruling. Attorney for Brandt, however, have asked for another review of Lathams's decision.

Brandt, who, under the county's rent control law, could collect rent increased from tenants while the matter was being decided, will have to refund more than $100,000 to the tenants if he loses his appeal.

The commission's December, vote angered members of the tenants' association and they alleged that the commission - and Hamilton in particular - had acted improperly.

Hamilton denied the allegations, stating that the countu's rent control law gave him authority to bring the case back before the commission. Hamilton, who originally approved Brandt's request for rent increases, said he still thinks the requested increases are justified.

The commission voted to discuss the dispute in private Tuesday after Assistant County Attorney Daniel J. Cassidy told them there might be civil litigation agains the board arising from the dispute.

Louis Hart, a spokesman for the tenants' association, said the Tuesday night vote indicated that commission members realized "they had gone astray" from provisions of the county's rent control law in their December meeting. Brandt could not be reached for comment yesterday.